EI dosing and discus tanks?


May 8, 2007
HEy all,

Well i have had a planted tank for a good couple years now, progressing as time goes along. I dose with ei and supply co2 through my pressurized system. I do my Ei dosing weekly and then my weekly water change of 50%.

I am now at the point where i am looking into different fish. I believe i will be interested into getting into a planted discus tank. Now my only problem is that i am curious to what will happen with my dosing scheduale with a discus tank.

Discus require water changes daily or every 2 days and this will greatly affect my ei scheduale. How do i counter these two things.

Tom Barr

Staff member
Jan 23, 2005
I raised and bred discus several years using EI.
This client of mine uses EI:


I'll let you decide.

Feeding is much more the issue, plants will actively remove NH4 directly.
NH4 and food waste are why do lots of water changes, however, if you wish, doing 2x a week 50WC's and dosing after is fine as well. You will just have less build up of nutrients and more stable ranges.

Water changes for non planted tanks and the build up of NO3 is not the same as KNO3 dosing. KNO3 does not start out as NH4 and high bioloading, it starts out as a relatively non toxic NO3. NH4 is 200-13000X more toxic than NO3.

So to add enough N for plants, KNO3 is much less stressful than simply adding progressively more fish(which also depletes O2 as well) that adds NH4 first and later is oxidized into NO3 via bacteria(which also uses up even more O2 for every N atom).

Not good.

Plants will use up most of the NH4 in a well balanced plant tank, but if you add too many fish, feed too much etc, then things can become a problem, this is due to low O2 and higher NH4 than the plants can use per unit time.

Lower light tanks, without CO2 etc can get all the N from fish waste, however, in high light CO2 enriched systems, we need to add N either to the water column or the sediment, or ideally, both locations and in the NO3 form.

Tom Barr


May 8, 2007
Wow, wish i knew my chemical numbers a bit more so i could understand that a bit better lol. Honestly probably got lost after the first line lol but i kinda got what your point was. Most of your replies you always specify in the first couple lines, then the rest of the post is just the geek talk haha, not to be rude...more of a jealousy issue , gotta read up more on this stuff.

It's funny cause you (as in me) actually think i know about this stuff pretty good, been doing this for about 6 years, upgraded my tank to a 55 gallon (started with a 5) got 2x65 coralife 6700, pressurized co2, ei dosing, uv sterilizer, eheim 2026, co2 misting, and i think i a pretty knowledgable...

But then try talking to you.. i feel like a noobie again haha. It's like i'm turning red virtually trying to keep up with you :)

Anyways lol.. what your trying to say "do 2 wc's a week , 50%, add ferts after and you'll be ok "

good to know.

Here's a couple pictures of my tank setup, just redid it, camera pics do not do justice of the tank when you see it though, kinda disappointing.