How much is BS?

How much of what nutrient makers is BS.?
They say to do a fresh res every wk. Why? Hell, I only have to adjust my Ph every 3 dys.
If res temps are kept stable to keep out unwanted growths why change?
Just like people say air pumps are necessary for res. In a DWC I can see it. But with a seperate res I see no need. I used to run them, but noticed they kept running the res temps up. Have went thru 2 grows since then with no pumps and cannot tell any difference in plant growth or production.
Just curious what other people's opinions are.

Nutrient makers have marketing departments.. and marketing departments are infamous for letting the truth take a back seat behind the hype. They make big claims that in a lot of cases simply aren't true. However nutrient companies don't make money from you adding an airstone/airpump so I think that aspect is irrelevant. I would agree that alot of the 'extra' supplements out there aimed at cannabis growers are overpriced and simply not worth it.

If you don't have an airstone/flooming or some sort of movement in the water then the water will be stagnant. Stagnant water will bread nasties pretty quickly, so in this case changing weekly is definitely a good idea. Also if your plants are using different elements of the nutrient at different rates you can end up with an imbalance until you next change the res, simply topping it up will not solve this. I change my res once a week, not because the nutrient company told me to do so, but because I know it's a good idea. If you ensure the water isn't stagnant (using an airstone for example) then you can easily go longer without changing the res.

So in summary I agree alot of the Nutrient Companies are full of BS.. but I don't think changing the res once every week or two weeks is part of that.

I use the spent res water to water my moms and do my clones. It works great for that. I try to change the res every five to seven days because I find it gives me better results. I was doing this before you could readily purchase hydro ferts.

I'm running a flood-n- drain feeding every 2 hrs so the water doesn't sit long. I also keep my res temps in the low 60's so I guess that helps keep res clean.
I tried they fresh res every wk, then switched to every 2 wks and haven't noticed any difference. On a small res changing every wk. wouldn't be that costly. But if you're running a large system then you can get into some money really quick.
That's not to mention all the snake oils they push for big buds. I think it's funny how much more the snake oils than the base nutrients.

PetFlora said:

I've used < 5g outboard rezes for 4-6 grows

What I have noticed is when the plants seem to stagnate it's time to dump 'old' nutes

I liken this to lighting, where assuming you provide all the spectrums that a plant needs, it will take what it needs (at that level of growth) and leave the rest.

When it comes to nutrients, it's the rest that gets out of balance. IF we knew which elements to replenish, and how much, we probably would not need to replace

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Excellent point, I guess I've just been lucky. Only have to PH bout every 3 dys. I check ppm's I just add to get level back up to desired ppm's and let it ride.
Now before someone chimes in and says I'm crazy. I'm not saying this is the way it should be done, but that it's the way I've done and it works for me.
Was just curious if there's other people who do the same way, or if I'm looking for disaster to strike.
I run Dutch Masters gold from start to finish and had great results.
Thanks for the input, I'm always trying to learn new things.

depends on the nutrients. Some if left in a resivor for 3 days, they start to build up a bio-film.. If you use organic and nutrients with lots of beneficial bacteria and such, you can get some nasty sludge build up in your feed lines.