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9 Posts
Discussion Starter · #1 ·
My tank has been running for 6 months now. the first 4 months every thing was great and I had no trouble.

The last month and a half things have deteriated seriously.

The set-up is:
Tank: 1220l X 63w X 50h (360 Litres) with 75L sump

CO2 : 3 x 2L DIY YEAST. The pH with out CO2 is 7.6 and with CO2 its 6.8

Light : 172 Watt
3 X 36Watt 6500K PC
1 x 3" AquaGlow 28W,
1 x 4" Phillips aquarell 36W

Duration: On for 5 hours of for 3 hours on for 6 hours = 11 hours a day

Substrate: 8cm thick 60kg 2mm filter sand + 1.5kg Laterite

Heating : 2 x 200watt heaters.

Fish : 11 Neons + 6 black Neons
7 Peppered Cory's + 5 Oto's + 3 CAE + 1 Plec ( 4cm)
6 Discuss and +- 20 Cardinals
1 Upside down catfish

ph : is 6.8 brought down from 7.6 using CO2
GH : 8
NO3 : 40ppm
Temp: 82F

My water changes has not been very regular in the past 2 months but the last 2 weeks its been back on 25% every three days to try and control the NO3.

I dose PMDD at daily. The mix does not contain P at the moment as I have not yet been able to find a local source of P. It also does not contain any NO3 as the levels in the tank are already very high.

What would cause the problems with the plants ? Would the lack of Potassium cause the problems ?

Any help will be much appreciated.


9 Posts
Discussion Starter · #4 ·

Edward said:
What exactly are you dosing and what is your KH and PO4?
I don't know what the KH is. My pH from the tap is 7.6 and I use CO2 to lower it to 6.8 - 7.

From the link I'm know pretty sure the problems is a Potassium DEFICIENCY The symptoms - Pinholes appear in older leaves, and slowly enlarge Yellow areas Withering of leaf edges and tips.

I'll try to find Potassium rather quickly.

Premium Member
7,965 Posts
I would suggest getting a KH test kit, it is much needed in a planted tank. If you know your KH then you can find out what your C02 levels are by also using PH.

166 Posts
Hi there

Nice to see another Joburger here :)

From the look of your photos I would say Traces + Macro's are the problem? You certainly don'thave a lack of NO3, perhaps you have too much NO3.
You say you don't have a source for P, I am dosing 'Fleet Enema' as a P source and it works just fine. The product has been renamed but if you ask the asisstants at The Randburg Waterfront chemist for fleet enema they will know which product you are after, perhaps Randburg is full of ppl with hectic constipation :p

Get your NO3 levels down to 15-20ppm and dose a couple of ml's of Fleet and I'm sure this will help out. Pottassium would not cause this!
You say you're not adding NO3 as the level is high already, Joburg water is pretty clean, like 0.01 NO2 and even less for Nitrates, where is your 40ppm no3 reading coming from? Check your test kit, don't trust it, possibly take a sample to the LFS for a second opinion. You need to start adding Macro's asap, your plants look hungry.

FWIW, the 1st & 3rd pics look like nutrient deficiencies and the 2nd pic looks like fish or snail damage? Hard to tell.

Kind Regards
Cameron James

3,819 Posts
I would increase the water changes to 50% daily, versus the 25% every other day. I recently had high NO3 and did multiple 50% water changes in one day to get the NO3 back to respectable levels. It did not bother the fish, even my Rams. The plants did not seem to mind either. Make sure you clean our your filter(s) including the hoses if it is a cannister filter and remove any decaying leaves from the tank.

Why are you turning the lights off for 3 hours mid-day? It seems just when the plants are fully consuming the nutrients (NO3) in your tank, the lights go out. They stop their uptake of nutrients, and then have to begin again when the lights come back on. It seems like it would make better sense to me to just leave the lights on and let the plants continue photosynthesizing.

You may want to read this post. While it deals with algae, Tom Barr explains a bit about a mid-day light siesta for plants.

Hope this helps.
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