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Persistent GSA/ GDA

Spider Pig

18 Mar 2008
Have had my tank set up in it's current incarnation for about 6 months now but still having problems with GSA on leaves and glass, and GDA on the glass.

Currently dosing 2 x EI using PMDD+PO4 formula:
"This is an example of EI for a 12 week supply for a 20 gallon tank for those with teaspoon adversion.

To 1 liter of DI water add:

60 grams KNO3
10 grams of KH2PO4
25 grams of GH booster

Add 5 mls daily."

So using 20ml/ day for a 180L tank. Use flourish 2 x /week. The reason I upped the dose was that I noticed a big burst in growth after a trim and the nitrate tested as 0 even with 1.5 x EI. Now it is 10ppm before WC
50% WC weekly. Admittedly I missed a couple of these a month ago but have been more rigorous with tank hygiene the last few changes.

CO2 is on 3 hrs before lights on and off 2 hrs before lights off. I usually have it at light green (pH6.4- 4kDH solution in drop checker) Although this is equivalent to a co2 of 50ppm odd, I haven't seen any adverse effects on my fish.
he only thing I can think of is flow. This might be a problem as the tank is quite heavily planted in the back right corner and although the juwel filter intake is positioned there, I don't think the flow is too great through the undergrowth. Planning a rescape in the new year to thin things out a bit.

Any other suggestions?



14 Nov 2008
On a mountain in the Highlands of Scotland

I had managed to nail all the algae in my main tank http://www.ukaps.org/forum/viewtopic.php?f=35&t=3898&start=20#p52875 except Green Spot on the leaves of my slower growing plants.

I knew the phosphates were not the issue as the levels in my tap water are between 5ppm and 9ppm, i was thinking variations in CO2 could be the issue as my supply isnt the best and i use a ph monitor (not good) for now.

I am waiting on a DIY reactor from Ed to sort that out but i have managed to sort my filter which was a Fluval 205 on a 174L tank, upgrading to a 405.

Now i don't have GSA. So in my case it was flow. Get a powerhead for your jungle. :D

I'm happy.

Best Regards,



Expert/Global Moderator
Staff member
11 Jul 2007
Chicago, USA
It's extremely unlikely that you have 50ppm CO2. Slowly add more along with more flow...

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