I wondered about O2 saturation so thats good to know.

I don't think light is my problem - or rather the limiting factor in my setup. I have 220 watts of compact flourescent lighting over a 72 gallon tank (w pressurized CO2 monitored at 6.3 pH - KH measuring 4 after water change) which I dose accordingly:

Day 1: 50-60% water change followed by 1 teaspoon Barr's GH booster, 1 teaspoon KNO3, 1/4 teaspoon of KH2, 70 ml excel

Day 2: 20 ml flourish, 10 ml excel

Day 3: 1 teaspoon KNO3, 1/4 teaspoon of KH2

Day 4: 20 ml flourish, 10 ml excel

Day 5: 1 teaspoon KNO3, 1/4 teaspoon of KH2

Day 6: 20 ml flourish, 10 ml excel

Day 7: stare at tank and wonder why I don't see more pearling

Looking at the EI recommended dosage schedule, I expect that this dosing schedule provides a little more than my plants need. And with that much light..... I'm surprised my plants aren't pearling/growing more (fairly new bulbs btw). I considered O2 saturation, but I suppose thats no longer an answer.

I also considered that I was miscalculating CO2 so I installed a drop-checker, but that indicated good levels of CO2. Although, I must admit that I didn't pay too close attention to the posts on this step. I filled the bulb with water from my tank (4dKH) and added about 10 drops from the reagent that came with my order.

Other than this I contemplated poor water flow as a reason for less pearling. However, my experience in the past with better performing tanks was that if I turned off the filter the pearling rate increased - or at least appeared to.

I've read enough posts and been doing this long enough to know that I'm missing something right under my nose...

Ideas?

Tom, thankyou very much for the reply I was desperately waiting for it. I have thoroughly cleaned the tank, scrubbed everything that I could. Have been changing 50% water every other day. The tank is looking much better than before. I have also ordered Excel. You got the problem right. I guess too much lighting and overdosing with fertilizer caused the algal bloom. I'll keep the things in check from now on. I am planning to move from my experimental 10 gallon to a 30 gallon tank. I hope a larger tank will be a better option.

My only concern is several conferences I have to attend in coming weeks and i'll be away for 5-7 days during each visit.

Yes, you do not need that much KNO3 etc.
You should see the effects.

So..........try slowly adding more CO2, increase movement of water.
CO2 on all night?
Ich!

Try adding it 1 hour before lights come on and 1before they shut off at night.
This will allow more to be added when you need it: only during the day.

High CO2 at night is not good for fish either and runs a higher risk of gassing them. When you add CO2 during the day cycle, you also have high O2, which can potentially mitigate the effects on fish health(exchange of CO2 and uptake of O2).

Back off the excel.

Use CO2 only.

Tap water is the next thing to look at, Cl, Na, Copper etc.........

Regards,
Tom Barr

Tom,

Took your advice with the dosing. I backed off excel and things have improved. Very interesting result - I had been under the impression that Excel kills algae and supplements CO2. From the results I'm seeing that assumption isn't entirely if at all accurate.

However - there is something else amiss, because my ludwigia repens are barely red at all... I'll work on water flow first, then check for contaiminants if things don't improve....

Mostly just wanted to say thanks for your help.

-Daniel Morris