PH on the rise?!?

[GoldenBoy77]

Hello again, I have another fish crisis going on. I have a 55 gallon tank planted pretty thickly and stocked with lots of different kinds of fish. My tap water has a PH of 8.5 out of the tap but now (only one day after a 50% water change) the PH is testing at 9.0. I added a handful of peat moss to the filter this afternoon and it doesnt seem to have changed. I've got 320 watts in lighting and I also have a DIY CO2 system that is putting out quite a few bubbles into the filter intake. The CO2 actually lowered the PH down to just under 8 the other day but today it's waaaaay up... 9.0 is scary, I'm really tired of losing fish (just getting thru with a battle with Ich... What is going on? Is it possible that the plants are using all the available CO2 in the water and raising the PH? Maybe I'll test it first thing in the morning and see if the results are different.
How long should it take to see an effect after putting peat moss in the fliter? I have an RO system ordered and on it's way (I expected it today, it never came) so this is only a temporary crisis... then I'm going to need advice on how much RO water to use...
Basically my question is, why would my PH go up? And, when will I see results from the added peat moss?

Thanks!

 

[freddyk]

I'm not sure why your ph keeps climbing despite the co2. What's the KH of the water?

I can tell you that peat moss is a waste of money and effort for you - it will not have any affect on water with as high perameters as you have.