Can someone explain to me how to top up a reservoir (rez)? I just don't get it...

[endogarden]

Sorry if this has been gone over, if so please direct me to the information! I am having some trouble wrapping my head around the concept of refilling a reservoir that still has nutrient solution in it. I'm specifically referring to flood/drain ebb/flow, but any recirculating rez would apply.

Let's say for example (I made these numbers up from recent experience), I add 20 gal of RO water @ 6.8pH and 10ppm, I add 5ml per gal of MagiCal, bringing the ppm to 260. Then I add veg nutes, upping the water to 850ppm. The pH has now gone down to like 4.5pH, so I add pH Up til it's at 5.6pH, the water is now 900ppm. I feed the ladies, afterwards the rez is low, they were thirsty.

Now I want to refill it, but (unlike I currently do), I don't want to empty the remaining solution. I cannot figure out how anyone is calculating their nute solution if you add more than one liquid to your rez, which I'm guess most people are doing.

So now I check the rez, say it's 6pH and 930ppm now. I add water to the rez, filling it back up to 20 gal. Now I check the pH and ppm, the ppm is now like 230ppm, like 6.4pH.

Of what is this 230ppm comprised? How can I possibly calculate the ratio of MagiCal I should leave out to compensate for the bit that remains in the rez from the original rez dosing? I want to have 250ppms of Calcium, Magnesium, and Iron from the MagiCal, how can I measure this if the solution has been diluted?

Please enlighten me as to how anyone and everyone are topping up their reservoirs. I'm guessing it's a simple thing I've over looked.

 

[CoreyPKGrower]

Hmmm... I used to be very anal about precise PPM values but found I was chasing my tail. Whats works best for me is a percentage of nutrients to water. Example. 100gal res. water only. Added 10ml/gal of Micro = 100ml total.
Knowing the reservoir is 100gal. If after watering The reservoir now has 80 gal left. Thats a 20% usage. So Now I top up tank with 20gal water and add 20ml of Micro. The PPM stays the same.... Or should on a flood and drain.

 

[cannibisox]

I normally top my reservoir off with distilled water, Plants tend to absorb more water than actual nutrients so you're left with a more potent nutrient solution and less water, so you just top off with water. However if your PPM readings are saying something else, then that's what I would go by but make sure your meter is working properly or maybe recalibrate it.

 

[Neumann]

Sorry if this has been gone over, if so please direct me to the information! I am having some trouble wrapping my head around the concept of refilling a reservoir that still has nutrient solution in it. I'm specifically referring to flood/drain ebb/flow, but any recirculating rez would apply.

Let's say for example (I made these numbers up from recent experience), I add 20 gal of RO water @ 6.8pH and 10ppm, I add 5ml per gal of MagiCal, bringing the ppm to 260. Then I add veg nutes, upping the water to 850ppm. The pH has now gone down to like 4.5pH, so I add pH Up til it's at 5.6pH, the water is now 900ppm. I feed the ladies, afterwards the rez is low, they were thirsty.

Now I want to refill it, but (unlike I currently do), I don't want to empty the remaining solution. I cannot figure out how anyone is calculating their nute solution if you add more than one liquid to your rez, which I'm guess most people are doing.

So now I check the rez, say it's 6pH and 930ppm now. I add water to the rez, filling it back up to 20 gal. Now I check the pH and ppm, the ppm is now like 230ppm, like 6.4pH.

Of what is this 230ppm comprised? How can I possibly calculate the ratio of MagiCal I should leave out to compensate for the bit that remains in the rez from the original rez dosing? I want to have 250ppms of Calcium, Magnesium, and Iron from the MagiCal, how can I measure this if the solution has been diluted?

Please enlighten me as to how anyone and everyone are topping up their reservoirs. I'm guessing it's a simple thing I've over looked.

Congratulations! You've hit the wall! What you're having is the same problem every hydro user comes up against. As far as I know NOBODY has successfully answered that question. There are different strategies, I'm sure you've researched them but what it all boils down to is, once the plants have taken in any nutrients, all bets are off for re-topping.

I can tell you what I do but it's only my preference, not The Way To Do It.

 

[PeaceFarmer]

Isn't that the reason for completely flushing and changing your rez every week (or two)? I simply use a sharpie to draw a line to where the water should be in the rez, everyday when my pump is OFF, I check the level, if it is low I top it off with enough water to bring it back up. I then adjust the ph and check EC values. Usually my 8 plants consume 5 gallons of water a week (consumption and evaporation of h20 out of the Rez). I add fresh h2o and nutes every Monday, so that I never have to worry about the EC during the week and don't have to worry about ratios, ppm, etc. Oh, I'm growing organic aero, but I'm sure it would work the same in a hydro set up.

 

[TurboKafer]

Isn't that the reason for completely flushing and changing your rez every week (or two)? I simply use a sharpie to draw a line to where the water should be in the rez, everyday when my pump is OFF, I check the level, if it is low I top it off with enough water to bring it back up. I then adjust the ph and check EC values. Usually my 8 plants consume 5 gallons of water a week (consumption and evaporation of h20 out of the Rez). I add fresh h2o and nutes every Monday, so that I never have to worry about the EC during the week and don't have to worry about ratios, ppm, etc. Oh, I'm growing organic aero, but I'm sure it would work the same in a hydro set up.

I agree with not over thinking and a simple fill up. When I grew in soil I thought that hydro was difficult and too much work. The truth is hydro/aero can be easy if you relax and don't make it difficult. Your concern is well founded but it is nearly impossible to gauge what your levels are past the point at which they were mixed.

Some growers use a top off mix that is a 1/3 strength but it's up to you.

 

[MEANGREEN69]

a 20 gal rez isnt that big. so you can find out what it takes ( nutes,Ph-up, cal/mag what ever) to fix a

1 or 5 gal jug. make sure you let it sit for AT LEAST 30 mins after mixing it up.

cause the Ph can change. then you can have it down to a science...see i know that it takes 3ml of Ph-

down, 5ml of cal/mag, 1 tsp of maxi grow for every gal of water to get it were i want it for veg. then

if i need more just mutiply..just my 2cents hope i helped.

 

[PeaceFarmer]

I know my first post up there didnt technically answer your question, rather just offered my opinion. So, if you wanted to be technical you could use a little bit of algebra to figure it out. I personally wouldn't do it this way just for the extra work it would take, but they are your ladies. So, say you only wanted to change your rez every 4 weeks or perhaps never. In order to top off with a solution that contains the ideal amount of nutrients, you must first determine the ratio of the original chemicals you have added. You add 250 ppm of Magical and 600ppm of Veg nutes (I omit the negligible 50 ppm from the ph up, as this value will change as your system begins to equibrilate and become steady). This means that you add 1 part Magical to every 4 parts of nute solution. So if your original ppm is 900 and your new value is 230ppm, you have a 670ppm deficit to correct. You should add 1 part of Magical and 4 parts of nutes (tsp or ml you will have to determine your own measuring value you wish to use, based on how big of an increment you want your ppm to change. For example you could make your units ml/tsp and obtain a very small change or use tbs and get a huge jump). Retest your rez solution and see what the ppm is. Get this value close, but under the 900 ppm you require. Now, add your ph down as needed to get your solution into the 5.8-6.2 range.

BIG UNKNOWN VARIABLE: Plants consume different amounts of supplements as it grows. During veg it may consume large amounts of NPK and rather small amounts of your CalMag. This could cause your ratio to begin to vary in your solution. For this reason, you should do a regular flush and get some fresh nutes/h2o in there. If you are an experienced grower, and can easily recognize the signs of nutrient deficiency by specific plant response, then it will be easy for you to do. You could start with your basic ratio, and then if you notice leaf curling or nute burn signs, you could back off the nutes and add a little water to dilute out the solution; same thing for the cal/mag with discolorations, etc. Check daily and adjust as needed. However, I still say to just change it out every 2 weeks or so, just so you can flush the salts out to prevent a nute lockout (I use Sledgehammer).

Hope this helps better than my first post.

 

[lordjin]

Technology can solve almost any problem. And for the lazy grower, automation is ideal.

While I agree with some of the other growers who say it's simply a method of working out your own routine, a float switch goes a long way. I just have an automatic topper that pumps fresh water from an external res every time the water level drops. This, of course, makes the ppm drop steadily, so I inject the res with the same nutrient mixture (saved in a jar as a concentrate) to get the ppms back up. I then add the appropriate amount of ph up fluid to balance.

Topping with a diluted solution doesn't work well with an automated external reservoir...it's just one more pump to get mucked up with gunk. Topping with pure water and manually injecting concentrate allows for greater control in my opinion.

Honestly, I would die without my float switch. I have no idea how so many of you guys live without one.

 

[endogarden]

Technology can solve almost any problem. And for the lazy grower, automation is ideal.

While I agree with some of the other growers who say it's simply a method of working out your own routine, a float switch goes a long way. I just have an automatic topper that pumps fresh water from an external res every time the water level drops. This, of course, makes the ppm drop steadily, so I inject the res with the same nutrient mixture (saved in a jar as a concentrate) to get the ppms back up. I then add the appropriate amount of ph up fluid to balance.

Topping with a diluted solution doesn't work well with an automated external reservoir...it's just one more pump to get mucked up with gunk. Topping with pure water and manually injecting concentrate allows for greater control in my opinion.

Honestly, I would die without my float switch. I have no idea how so many of you guys live without one.

Okay I totally feel you, I have a float switch in my 130gal ro tank to auto fill it, and I also have float switches in my three 27 gal nute rezs.

How do you get the water rez to refill the nute rez (or rezs in my case)? Gravity? A pump that's electrically connected to the float switch? Currently I use a pump that I have to plug in to refill the rezs.

Also, when do you inject the solution, and is it the original solution you would put in a fresh rez, or a modified one to account for the increased level of ppm (compared to a fresh rez filling)?

 

[endogarden]

I know my first post up there didnt technically answer your question, rather just offered my opinion. So, if you wanted to be technical you could use a little bit of algebra to figure it out. I personally wouldn't do it this way just for the extra work it would take, but they are your ladies. So, say you only wanted to change your rez every 4 weeks or perhaps never. In order to top off with a solution that contains the ideal amount of nutrients, you must first determine the ratio of the original chemicals you have added. You add 250 ppm of Magical and 600ppm of Veg nutes (I omit the negligible 50 ppm from the ph up, as this value will change as your system begins to equibrilate and become steady). This means that you add 1 part Magical to every 4 parts of nute solution. So if your original ppm is 900 and your new value is 230ppm, you have a 670ppm deficit to correct. You should add 1 part of Magical and 4 parts of nutes (tsp or ml you will have to determine your own measuring value you wish to use, based on how big of an increment you want your ppm to change. For example you could make your units ml/tsp and obtain a very small change or use tbs and get a huge jump). Retest your rez solution and see what the ppm is. Get this value close, but under the 900 ppm you require. Now, add your ph down as needed to get your solution into the 5.8-6.2 range.

BIG UNKNOWN VARIABLE: Plants consume different amounts of supplements as it grows. During veg it may consume large amounts of NPK and rather small amounts of your CalMag. This could cause your ratio to begin to vary in your solution. For this reason, you should do a regular flush and get some fresh nutes/h2o in there. If you are an experienced grower, and can easily recognize the signs of nutrient deficiency by specific plant response, then it will be easy for you to do. You could start with your basic ratio, and then if you notice leaf curling or nute burn signs, you could back off the nutes and add a little water to dilute out the solution; same thing for the cal/mag with discolorations, etc. Check daily and adjust as needed. However, I still say to just change it out every 2 weeks or so, just so you can flush the salts out to prevent a nute lockout (I use Sledgehammer).

Hope this helps better than my first post.

Yup that variable is the thing that gets me. What confuses me is when I feed all three of my flood tables the same thing, and a few plants on different tables, on each table, show different deficiencies. Some leaves are turning a gradient of dark pink/purplish to yellow, which I think is cal mag related, some have a few "rust spots" on the lower leaves, some colas have 3 or so completely yellow fan leaves (some colas have all deep green fan leaves), some look absolutely perfect. I can't determine why there is such a broad range of minor issues, the overall is doing great, but it's peppered with minor random-seeming issues. It's Week 7, Day 5, so 54 days flowering.

It's seeming like the top up strategies seem to involve trying to maintain a decent solution for a week, then renewing it. So it's like a week long stretched drain to waste, instead of a one feeding session drain to waste, in a way.

 

[endogarden]

Okay, I may have figured this concept out just now. [THREAD UPDATE]

I have a 55gal barrel for a rez now, fuck the 3 27gal tote rezs I was using, those are gone. I filled my rez to 50gals (for easy math) and added all my lovely plant liquids until it got to 900ppm, then I fed, then I was left with 15gal of 900ppm solution.

So then I waited 2 days, and now I topped up the 15gal with RO water until it was at 50gal again, meaning I have added 35gal of unaltered RO water to the mix.

Then I just calculated my nutrient ml-to-gal ratios with 35 instead of 50 (like I would for a full rez).

I then raised the ppms to 1000 (by adding more FloraNova Bloom), then added 0.5ml per gal aka 25ml of HCO Gravity to the mix, as I am 2 days from hitting week 4.

I think I got it, it was just too hard to grasp with 3 different rezs doing 3 different things. Damn that sucked. Now everything's awesome, and soon I will get a CAP Ebb & Gro Controller bucket to flood/drain my 3 trays sitting on the floor, so I won't have to hand water any longer.

Edit: Oooo I just realized that the only reason this works is because it is drain to waste. If it was recirculating, then the plants would absorb different amounts of different nutrients and the solution that returned to the rez would not contain the same ppm of each nutrient as it did going in. So then the top up mix would be off/variable again. So perhaps I won't get the control bucket after all.

I have been thinking of doing an experiment where I just put airstones in the trays, and have float valves in the trays at about 1.5" above the bottoms of the root pots, having the 55gal rez gravity feeding all 3 trays continuously through the float valves, allowing the plants to drink as much as they wanted from the bottom up, soaking up through the coco coir filled, root pot bottoms. This solution would always be kept at 1.5", and aerated. This way I would never have to manage the plants nutrients, just provide ample amounts of them at the right times. My hypothesis is that the plants would select what they needed and be very healthy.

What do you guys think?

 

[MEANGREEN69]

good to hear you figured it out...i like the idea of the airstones in the trays. i have wanted to do something like that for a while. but was thinking of just letting the trays stay flooding and draining with the airstones running 24/7.. was thinking of getting those big round ones ( about 3 inches) and setting them in pot before i transplant, i often use JUST perlite as a medium. i think it will breath well. if you do end up doing this make a thread i whould like to check it out for sure.

 

[hellraizer30]

first off 20is gal res aint going to get you much time so if I were you upgrade to a 50gal this if your plant count is under 25 will buy you a week
without add back, during add back add plain water check ppms take that number whaterever it is? then take your normal feeding formula and start
in small amounts till you get your target ppm# you want. then add your ph down or up to get your 5.8 in total you should add back once a week
and total res change every 2 week. if you still have issue hit me up

 

[endogarden]

good to hear you figured it out...i like the idea of the airstones in the trays. i have wanted to do something like that for a while. but was thinking of just letting the trays stay flooding and draining with the airstones running 24/7.. was thinking of getting those big round ones ( about 3 inches) and setting them in pot before i transplant, i often use JUST perlite as a medium. i think it will breath well. if you do end up doing this make a thread i whould like to check it out for sure.

Will do. I got the idea from a Maximum Yield article (http://issuu.com/maximum-yield/docs/my_usa_may_2011?viewMode=magazine&mode=embed go to Page 96) where they say:

"What is the final answer? Use a hydroponic growing system that maintains a constant level of nutrient solution in the base of rooting vessel, and a rooting medium of perlite, composted milled pine bark, or possibly even rockwool or coir - substances that have long-term physical and chemical stability as well as a 'wicking' characteristic. The plant itself is now in control, absorbing water and nutrient elements from a constantly maintained rooting environment, and requiring a nutrient solution with a low elemental concentration (ppm). The major advantage when using this system is that all of the applied water and nutrient elements are utilized by the plant. There is also a better chance that plants growing under such conditions will remain in a condition of nutrient element sufficiency, and will be more likely to reach their maximum biological potential."

first off 20is gal res aint going to get you much time so if I were you upgrade to a 50gal this if your plant count is under 25 will buy you a week
without add back, during add back add plain water check ppms take that number whaterever it is? then take your normal feeding formula and start
in small amounts till you get your target ppm# you want. then add your ph down or up to get your 5.8 in total you should add back once a week
and total res change every 2 week. if you still have issue hit me up

Well I was using 3 20gal rezs, filling each and feeding one tray with each one, ebb+flow style. I then had to drop the trays and go to drain to waste because of height issues. So then I was refilling three 20gal rezs every time I fed and it was a huge PITA. So I got a 55gal barrel to replace all 3 rezs and now everything is going well, instead of using around 45 gal in 3 rezs to feed, I am now using 35gal to hand-hose feed 3 trays. So it doesn't really buy me any time, but everything is working much better and I have a much better handle mentally on the problem.

 

[hellraizer30]

well it would get you time if you were on a recycleing but drain to waist isnt what your threads about. owell

 

[endogarden]

well it would get you time if you were on a recycleing but drain to waist isnt what your threads about. owell

Don't get me wrong, thanks for the input, and I wasn't negating your insight into saving time, I was just relaying my current situation.

 

[hellraizer30]

its cool glad you got it all worked out

 

[karmeron]

you can also use the lucas formula with his top up calculator formula, seems to work for a lot of people including myself.

 

[johnwest221]

[quate]

• When replacing water, you’ll want to replace the nutrients in it too, especially after your plants mature and start drinking more than a gallon of water a day. In the beginning, you can probably get away with topping off your water with plain, pH’ed water. You can figure out how much nutrients to add to your top-off water by applying the following formula: Take the number of gallons you’re putting back in the reservoir, and divide that number by the total number of gallons in your reservoir. So, if you’re adding in 1 gallon, and your total number of gallons is 5, your number is 1/5. The resulting number is the fraction of your normal nutrient dose you’ll need to put back in the tank (I always like to put a little less than whatever number I ended up with). If you end up with a fraction of 1/5 like in the example, you’ll add 1/5 of your normal nutrients (or a little less) to the 1 gallon of water that you’re using to top off the reservoir.
  • The easier way to do this is to make an extra batch of nutrient water and use that to top off your reservoir. Nutrient water can last for at least 2 weeks after being mixed.
• Minerals will build up in the reservoir and your plants may not use all the nutrients equally, so you’ll definitely want to change the entire reservoir of water at least once every 7 days.
• The plants like the 10-15min of oxygen they get while you’re changing the water, but don’t let any of the roots dry out.

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