EI & Discus

[timmo11]

Hi

Here are some brief details of my setup. I have planted 200L tank with CO2 injection, a pH-stat system, pH=6.50, dKH=2-3 (=> CO2 ~ 20-30ppm) and about 120W of fluro illumination via double ballast overdrive of T8's.

I keep about 30 small fish + 2 Discus. Up until now I have been doing things the "standard" way with the aim of reducing PO4 & NO3 by adding plenty of Trace (Flourish) + extra iron + extra K2SO4, and a 25% change every 2 weeks. The plants are doing OK-ish, the fish are doing great and the NO3 and PO4 levels are zero to low. No problems with algae since adding plenty of the ferts described above.

I haven't been measuring or doing anything about the GH. I wanted it low for the Discus, and Sydney has very soft tap water.

What I have read here is a real eye-opener - basically I am getting the NO3 & PO4 down by starving my plants. The whole EI method appeals to me much more than what I am doing now.

My one reservation is how will the Discus go with up to 30ppm NO3, and with me adding Ca + Mg to raise the GH? From everything I can find, Discus like very soft water with very low nitrates. Has anyone used EI with Discus, and how did the fish go with it?

Thanks

Tim

 

[Tom Barr]

The big issue is drought in Oz, so doing more water changes might not be the best idea, nor keeping large Discus.

ADA also suggest 50% weekly water changes, more if things are not doing well.

EI suggets this also, but this is to keep nutrients in a target range.

You only do 1/4 of this.

Check to see if you are wiling to do this increase, and can do something with the waste water(plants, landscaping etc, the lawn etc).

If not, we can modify things somewhat.

Discus honestly do not care even a little about NO3's.
That's just a fish only parameter that says do a water change due to over feeding and all the waste which starts as NH4, KNO3 dosing is an entire other thing.

CO2 is the parameter that is most likely to cause issues for fish(all fish).
Discus seem fine up to 45ppm using really good measurements and behavior and coloration, feeding etc.

With the lower light you have, you are in good shape.
I'd go maybe 25% 2x a week water change and dose about 1/2 full EI dosing.

Or go 50% once a week.
Whatever is easier for you and gets the job done.

Here's the tank, this guy adds 1/3 cup of KNO3 daily:

My Altum tank:

Regards,
Tom Barr

 

[timmo11]

Hi Tom

Thanks so much for your quick reply.

The drought has more or less broken here so water is not such a big issue as it would have been 2-3 years ago.

It's really interesting discovering that NO3 is basically measured as a proxy for other toxins, and that adding it directly as KNO3 is nothing to be worried about (within reason).

I really appreciate that you have given such tailored advice. I'll follow it for 4 weeks and go from there.


Tim

 

[Tom Barr]

Tim, there is a good artilce here in the article's section of fish an toxicity.

http://www.barrreport.com/articles/3267-no3-nh4-toxicity-test-plants-critters.html

A good review for NO3:

- Google Scholar

In this paper, which you may or may not have access to for the full article, the fish are extremely high, 200ppm or more for N-NO3, so this is about 800 ppm for guppies etc and warm water fish are much less sensitive to NO3 overall. Also, adding salts, lik KCL and other ions reduce the toxicity. So adding GH booster might help some, K+, PO4, etc, higher KH's say in the 2-3 range.

And for NO2, which is pretty bad also and last much longer in the systems:
http://afs.allenpress.com/perlserv/...77/1548-8659(1986)115<183:TONTF>2.0.CO;2&ct=1

Regards,
Tom Barr