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Whats in your top off tank?

Gadget Man

I am introducing a 32gal top off barrel to my grow with a float.
I've heard conflicting information about what goes in it.
Some use only OR water (which dilutes your nutes slowly).
Some use the exact same PPMs found in the control res.
I'm sitting here with a full tank about to flip the switch to introduce top off. I need your input before I do.
What can I say. I LOVE Gadgets.


Member of the Month: May 2009, Oct 2010, Sept 2017
With me, it was a question of what (inasmuch as I could tell) the plant needed. IOW, if it appeared that the plant was thirsty - consumed more of the water than nutrients, causing the solution to become more concentrated - then I'd add back water, or mostly water. If, OtOH, it looked like it was thirsty [/i]and hungry[/i], I'd add back something akin to what I was filling the reservoir with to begin with. If the plant seemed to be more hungry than thirsty - concentration of the nutrient solution went down - than I'd use something stronger when topping off the reservoir.

...and that's probably why I never ran any kind of feeder reservoir, lol.

But, really, it's whatever your meters, your plants, and your eyes tell you. If I was going out of town unexpectedly, I'd use a best guess based on current readings (along with, hopefully, a few more). If this was a regular thing, though, I'd rebuild with significantly larger reservoirs instead of using a feeder tank. (There might always be a potential need for a bit of insurance during an emergency absence, though.)

If I did decide that a feeder reservoir was appropriate, I'd want to add the ability to monitor/adjust pH at a minimum (the dosers I've seen will only correct in one direction), and a nutrient doser (or set, I suppose, depending) and monitoring device wouldn't be a bad addition, either.

Gadget Man

Thanks for the input.
I went to the grow store today. His method is watch the EC and PPMs. Let the top off tank do it's thing by adding water. Figure out how much water it drank and add nutes to get you back to where you were. Now that I type it out loud (?), It sounds like math. I bet the bluelab pro controller could do it. Damn, I love gadgets.

I just grabbed a filter today. I can't wait to cut it in.


Photo of the Month: Jan 2019 - Plant of the Month: Feb 2019
The biggest reason for the drain n flush is to reset/change the depleted npk ratios. Use a top off tank with normal nutes if you need a longer interval between changes than your normal reservoir can hold. Adding to an active mix will change things you can't control. Even with a bluelab
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