Water Column Dosing?


Lifetime Charter Member
Lifetime Member
Jan 24, 2005
A few years ago Tom and others posted about adding all required nutrients to the water column and using the substrate just to hold down plants.

I was never able to get this to work very well in my non-co2 tanks, including the one I set up three months ago. The plants in that tank live but they don't grow very much, whereas in my soil-based tanks they grow like, well, weeds.

In this 10 gallon tank nitrates and phosphates are at the proper levels, I add Flourish every now and then, and Excel at least weekly. Light is a little over 2 WPG, which is enough in another 10 gallon tank. It contains about 15 guppy-sized fish.

Is anybody using water column dosing with an inert substrate?


Tom Barr

Staff member
Jan 23, 2005
Re: Water Column Dosing?

Well, stop adding Excel once a week first off, either add it daily/every other day, or not at all.

I've used old mature onxy/flourite with good success + water column dosing.

You probabkly were not adding enough nutrients to the tank.
Many folks dose the same amount to a substrate enriched tank as the inert substrate and then like to say the enriched substrate does better.........well, that is true if the inert substrate tank is limited.

Adding 1(S)+1(WC)= 2, that's the enriched substrate
Adding 0(S) + 1(WC) = 1, that's the inert substrate, you need to dose more if you plan to rely solely on the water column.

Likewise, if you plan to solely rely on a substrate source: you need to add a fairly rich nutrient based.

Doing both will give you the best result and the best growth.

Tom Barr


Prolific Poster
Jan 30, 2006
Re: Water Column Dosing?

aquabillpers said:
Is anybody using water column dosing with an inert substrate?

Yes. I have just plain gravel... and it is working well :)

The tank has been set up for 7 months. I took the gravel and ALL the accumulated sediment from a 7 year old tank that it replaced.

Sometimes with and sometimes without (DIY) CO2.