Did a gravel vac of the areas I could get to, which wasn’t done since 12/28/09, and a coat of algae has formed over the top that was exactly like it was before, adhered to the gravel and thick enough where it wouldn’t get sucked up the vac tube. I guess I am going to have to hurry up and get him some snails and hermits, or stir the gravel a couple times a week.
I will also admit something kinda stupid on my part, especially since I’m an engineer and should be able to calculate volume pretty easily. The tank is not a 135, it’s a 125 Long. 72x18x20. I don’t know where I came up with 135. I figured it out when I was calculating how much water to remove. Here’s how I do that, in case anyone is interested:
1 cubic foot of water = 7.5 gallons (7.48, but who cares).
1 cu ft = 1728 cu in
Inside dimensions of125L is 71-1/4 x 17-1/4.
Overflows are 7” on a side, ¼ round, so 2 of them I just called 7x7, when you subtract that off the interior, it’s about 1180 sq in.
1728 / 1180 = 1.46 in (= 7.5g).
So removing 80 gallons would be 80 / 7.5 = 10.66 cu ft, or 18432 cu in.
18432 / 1180 = 15.6 inches.
When I measured that, I figured out that I was not correct on the size of the tank. Oh well. That means I’ve been doing a little higher % of PWCs, which in turn means that the Nitrates and Phosphates are being produced at a higher rate than I previously thought, and also that the initial Nitrate level was probably higher. Now take a breath, because I did a backwards calculated what the Nitrate level was before I started anything by taking the latest reading and extrapolating what the Nitrate level would be at prior to that water change, all the way back to the beginning using the formula (NO3
after water change) divided by (1 minus the percentage of the water change) to come up with the Nitrate level before the water change. For instance, if I tested 80 ppm
after a 53% water change, then 80 / (1-.53) = 170. Those are the actual test numbers and PWC
%s from the test on 1/12 and PWC
% on 1/11. Going backwards, PWCs were 36%, 36%, 36%, 27%, 25%. If you plug those number in, the Nitrate level was originally 1169. Of course, Nitrates were probably being produced, but those PWCs were all done within a 30 day period starting 12/13/09 and ending 1/11/09. So they couldn’t be increasing that fast!!!
Pics and test results tomorrow. Ciao!