Is reservoir water change really necessary after all...

Hi, I used to change and throw away feeding water closer to flower or in flower every 3 weeks what ever was in reservoir
and then sometimes not.
this time I have quite a few tanks which are between 40-50 gallons and I am not sure if it is absolutely necessary
to go and pump away expensive nutrients even the EC reading keeps rising or just to add water .
The plants are looking good ,(ok ,if really analyzing , one strain a bit fluffy and the other strain 5 weeks in to flower showing some amber pistils its a 8 week strain) ...but in overall good...
Do somebody of you pros or long timers just add new fresh top up water and a bit of nutrients or do you swear by the need of throwing away nutrients regularly to stop the in balances in nutrient solution...yep I know about the plants using sometimes this and sometimes that and leave behind imbalanced solutions and thru that maybe toxic feeding water....what do you guys swear by ?

There are several answers to this question.
Short answer is yes.
The plants are using the nutrient. The total nutrient amount is lowering! They are adding back waste materials that effect the EC or ppm. This is the rising part your seeing.
Your plants are getting less nutrition as a result. These "waste" buildups can hurt the plant also.

Ever hear of the 33% add back rule? Old but effective way to add back and, know when to dump and refill with fresh.

Fill your tanks with 100% fresh nutrient mix. Note the amount (volume) used in each.
Now, as the tanks lower in levels and you add back nutrient to the original volume.
Add back at 33% concentration of the nutrient - Make a gallon of 100% nutrient mix. Now add 2 gallons of your plain water and pH. This is your 33% add back mix.
Add back that 33% mix to top off to the original volume.

Keep adding back at that 33% till your going to reach that total amount you filled the tank to that first 100% time you started with.
At that point, dump and refill with fresh 100% mix.
Repeat till done with the run. Veg or Bloom...

Example: If you filled with 50 gallons of mix. You top off 5 gallons of 33% at a top off.
On the 10th time you would add back - Dump and refill with fresh 100% mix.

Great for DWC too!

I'm sure your going to get more then a few answers. I assure you, this one works well.

Good luck.

Dr. Who said:

There are several answers to this question.
Short answer is yes.
The plants are using the nutrient. The total nutrient amount is lowering! They are adding back waste materials that effect the EC or ppm. This is the rising part your seeing.
Your plants are getting less nutrition as a result. These "waste" buildups can hurt the plant also.

Ever hear of the 33% add back rule? Old but effective way to add back and, know when to dump and refill with fresh.

Fill your tanks with 100% fresh nutrient mix. Note the amount (volume) used in each.
Now, as the tanks lower in levels and you add back nutrient to the original volume.
Add back at 33% concentration of the nutrient - Make a gallon of 100% nutrient mix. Now add 2 gallons of your plain water and pH. This is your 33% add back mix.
Add back that 33% mix to top off to the original volume.

Keep adding back at that 33% till your going to reach that total amount you filled the tank to that first 100% time you started with.
At that point, dump and refill with fresh 100% mix.
Repeat till done with the run. Veg or Bloom...

Example: If you filled with 50 gallons of mix. You top off 5 gallons of 33% at a top off.
On the 10th time you would add back - Dump and refill with fresh 100% mix.

Great for DWC too!

I'm sure your going to get more then a few answers. I assure you, this one works well.

Good luck.

Click to expand...

Oh yeah, we used to take our dump solution and water the lawns with it.....Why waste?

Phytium hater said:

Do somebody of you pros or long timers just add new fresh top up water and a bit of nutrients or do you swear by the need of throwing away nutrients regularly to stop the in balances in nutrient solution...yep I know about the plants using sometimes this and sometimes that and leave behind imbalanced solutions and thru that maybe toxic feeding water....what do you guys swear by ?

Click to expand...

I've been doing DWC since '01 and after a lot of trial and error, no internet until '09, just change my nutes once each run after the stretch is over when I go with the Lucas formula and some Big Bud. RO water only so no interference from minerals in the water to contend with. With the AN nutes I just top up the tub and check PPM. If it's dropped I use syringes to squirt small amounts of nutes in the proper ratio to bring it back up near my target level.

I've often done a whole run without changes at all and really haven't seen any harm or reduction in yields tho not keeping exact track of the details.

At least for the veg period there is no solid reason to be tossing out perfectly good nutes every week like they tell you to. That's pure waste and designed to make them richer. I might start changing nutes twice to see what happens. Once at the flip then again after the stretch. I like to dose my plants with a 1-1-1 ratio of the 3-part and a half dose of Big Bud a week before flipping to "prime the pump" so to say. Seems to work really well with bud sites popping out where I didn't think any would and golf ball sized colas after 3 weeks that have grown bigger than my forearm at the finish.

My biggest problem has been very low RH and even running my nutes at lower levels has resulted in toxic salts buildup that causes the fan leaves to start burning and ending up hard, thick and crispy progressing as far as the bud leaves when it was bad. I thought it was due to N toxicity but clued into vapour pressure deficit and finally figured it out. My last bigger grow was in a 50:50 mix of ProMix HP and ProMix potting soil using AN 3-part at half the strength I would normally use and no dried out fans at all. As the finish neared the fans stayed soft an pliable until they were pure yellow and came off with a gentle tug. I know I'm on the right track now and rather than try to keep my RH up I'm going with lower PPMs in DWC and see how that works.

As long as there is some of everything in the nutes and you can read your plants decently it's easy enough to feel that the plants may be lacking in one thing or another and add a bit of what it needs to keep it happy. I like to powder a couple zinc tablets, Vit.Cs, selenium and some of my B-Complex caps and toss them into the nute mix too. Iron too if I have any. Not sure if it makes a difference but they keep me healthier so why not the plants.

OldMedUser said:

At least for the veg period there is no solid reason to be tossing out perfectly good nutes every week like they tell you to. That's pure waste and designed to make them richer. I might start changing nutes twice to see what happens. Once at the flip then again after the stretch.

Click to expand...

If you raise the P&K as any type of "boost". You need to dump and refill, without those for the last 2 weeks. Your supporting better THC levels that way. You also stop any Mg use at that time also. Same reason.

The old school thing I supplied was done back when Hydro was new.... We encountered problems that were later discovered to be avoided by this method. I used this as a rule, even as nutrient lines progressed and hydro specific nutrients were used. I never had an issue and, just think how long it takes to get to that 10th refill with a 50 gallon tank anyway.. So, basically, it's about the same as far as dumping goes....

As far as after the stretch? Damn straight if you run a veg or higher N mix for the stretch.....

I found it super useful in fast turn over DWC situations. The waste issue will pop up faster and that helped out big....

33% is a safer add back ratio to even start with. Many swear by their 100% add backs and I suspect newer, better formulated for hydro nutrients being a key point in that.
Still, it's easy and adds a measure of a "safe zone".....

If you use a 3 part.....I seriously suggest it. Use of a "Zyme" product does help the waste issue a bit too.

I stop any use of boosters or almost all nutes around week 5 or 6 with an 8 week strain and a week or so before I figure they are ready I will pump out enough of the nutes to get the ppm down to around 200-300 after topping up with RO.

I want a bit of nutes in there as I crop in stages over a couple of weeks but like to see fan leaves yellowing well before the initial chop to know they are going to be cleaner and are cannibalizing themselves to finish up.

I've tried AN OverDrive at the end but a side-by-side comparison didn't show any noticeable increase in bud size or resin so won't be using it any more.

Never have any dead roots or slime to take care of so never bothered with any beneficial bacteria/fungi Zyme type products. I can keep my nute temps around 65-68F and that seems to be the ticket.

OldMedUser said:

I've often done a whole run without changes at all and really haven't seen any harm or reduction in yields tho not keeping exact track of the details.

Click to expand...

x2

i just refill with water, check my TDS and jack it up to 1200-1600ppm

How are you irrigating?
Are you using a flood and drain system, drip to waste, etc...
Recirculating systems much be changed out periodically.
I have a gravity fed system using a reservoir and blumats. I never change out the reservoir because the solution isn't being recirculated as a flood and drain method would. I just keep it filled. If you'r recirculating the solution then yes a change is necessary.

Dr. Who said:

Oh yeah, we used to take our dump solution and water the lawns with it.....Why waste?

Click to expand...

I used to dump it in the garden plot. Flowers in pots on the patio also like waste water.

xtsho said:

How are you irrigating?
Are you using a flood and drain system, drip to waste, etc...

Click to expand...

I use RubberMaid tubs to do my DWC so no recirculating. Just a couple 12" airstones in there to keep everything mixed up and well aerated.

Sour Wreck said:

x2

i just refill with water, check my TDS and jack it up to 1200-1600ppm

Click to expand...

That's way too high a PPM with my low RH. I'm going about max 750 for now on.

xtsho said:

How are you irrigating?
Are you using a flood and drain system, drip to waste, etc...
Recirculating systems much be changed out periodically.
I have a gravity fed system using a reservoir and blumats. I never change out the reservoir because the solution isn't being recirculated as a flood and drain method would. I just keep it filled. If you'r recirculating the solution then yes a change is necessary.



I used to dump it in the garden plot. Flowers in pots on the patio also like waste water.

Click to expand...

not sure if you were asking me or the OP, but i run DWC

I never do anything to my Tank,other than give it a really Good Clean,after each Grow.I think has long has you have a Decent Pump sending air to the res,And really moving the mix around ,then all's good ,I suppose it dep,on the size of tank,I only use the res i have for 2 plants ,So with in 2 days its near enough Empty any how,If it was a big tank then i would more than likely clean after each Phase of the grow,I use a One part ,Nute.When i used to use a 2 part like Advanced Sensi pro a/b veg Then A/b Bloom ,then i all ways cleaned the res.The amount of Salt that builds up on the tanks is un real ,If you do not use a Pump,I also use a air ring in the bottom of each pot ,where air is sent to the roots ,Air been pumps to any water/nutes,is key to keeping that mix good,I also Sometimes Clean ,the res after Big Bud from Advanced ,that seems to leave a kind of Slime .I would rather make a fresh batch of Nutes up every couple of days,Knowing that they are fresh made ,than make a massive batch up and have them sat around for ages,But each to there own,I have done both and found by making small batches up every two days i have less Problems.But i'm sure some will disagree ,each grower does things different.

Thanks guys, well I did now the all 4 big tanks emptying and refilling it was a huge task...and of course did I fuck around and knocked over some pots because at some of the tanks its really hard to get a big pump in them when the plants are covering the lids..so I had to take the whole system apart...well its done...I used to be more exited with the reservoir changing in the past but at some point just got lazy and realized plants where pretty ok anyway....

Everyone says yes because it is the safe way to go but it's not necessary.

Last run in my my DWC res, my plants had a 3.5x stretch and I couldn't lift the lid to change the res because the plants were taking all the height. So I didn't change the res for the whole run and everything went fine. My plants drank a gallon a day anyway so there was plenty fresh water.

Phytium hater said:

Hi, I used to change and throw away feeding water closer to flower or in flower every 3 weeks what ever was in reservoir
and then sometimes not.
this time I have quite a few tanks which are between 40-50 gallons and I am not sure if it is absolutely necessary
to go and pump away expensive nutrients even the EC reading keeps rising or just to add water .
The plants are looking good ,(ok ,if really analyzing , one strain a bit fluffy and the other strain 5 weeks in to flower showing some amber pistils its a 8 week strain) ...but in overall good...
Do somebody of you pros or long timers just add new fresh top up water and a bit of nutrients or do you swear by the need of throwing away nutrients regularly to stop the in balances in nutrient solution...yep I know about the plants using sometimes this and sometimes that and leave behind imbalanced solutions and thru that maybe toxic feeding water....what do you guys swear by ?

Click to expand...

I have always done run to waste or what's left I dump in a 14 day period even if there's 10-15 ltrs left I dump it I always have they seem to grow a bit better not much but a bit better now my mate never dumps ive looked in his rez and its bright green but they do well I do 10-15 were he does 30+ plants he has never had a issue

newguy123 said:

Everyone says yes because it is the safe way to go but it's not necessary.

Last run in my my DWC res, my plants had a 3.5x stretch and I couldn't lift the lid to change the res because the plants were taking all the height. So I didn't change the res for the whole run and everything went fine. My plants drank a gallon a day anyway so there was plenty fresh water.

Click to expand...

I always make a 2" inspection hole in my tub lids so I can use a drill pump or shop vac to empty it if needed or to add water and nutes. I like my DWC ScroGs and without it I'd be screwed.

How do you do that stuff?

OldMedUser said:

I always make a 2" inspection hole in my tub lids so I can use a drill pump or shop vac to empty it if needed or to add water and nutes. I like my DWC ScroGs and without it I'd be screwed.

How do you do that stuff?

View attachment 4058688

Click to expand...

Installed a Bulkhead gasket with a ball valve on the tank and a fill hole like you mentioned. You need a hard tote for Bulkhead though. If you use a soft tote like yours it will be doing as you fill the res and will leak.

Blumats
Watering solved and simplified

When i run my RDWC system i change the water on it once every week, it's easy just drain it and then fill from top, no need to lift buckets if your setup is correct.