Well, I did measure the other day when I had to put in about seven
inches or so, when max gallons is 2200. That one did require addition
of the amquel. But, I didn't need to add more than a bottle. Checked
it later and it was ok.

You're using liquid Amquel? That could be part of your price problem. Dry
form is cheaper to buy and ship. Another brand name is ChorAm-X, cheaper
than the Amquel brand.

www.aquaticeco.com is one place that sells both dry, I believe, worth
googling or foogling to find the cheapest price. ~ jan

~Power to the Porg, Flow On!~