So I have used vinegar in the past to clean without issue. The current tank got a vinegar bath, but still had some old algae left over in the corners and on the back. I decided to order some citric acid from Amazon (https://a.co/d/dnH0eGR - Pure Citric Acid 5 LB Bulk Bag - 100% Natural, Food Grade, Non-GMO - Citric Acid Powder for Cleaning, Bath Bombs, Preserving | Fine Granular | Premium Quality by Spicy World) and dump it in the tank with water to circulate. Figure it would help clean out the piping, bubble traps, overflow, weir teeth, etc.
I did 5 lbs to ~150 gallons of water (so about 1lb per 30 gallons of water). It seemed to get to work right away, watching the algae on the bottom bubble instantly. I turned the whole system on, so I let it run through the sump and back up. My only "complaint" is I still have to scrub. It softened it up, and in some spots it did flake off, but there are some spots, where it comes right off, but I need to physically touch it.
I did 5 lbs to ~150 gallons of water (so about 1lb per 30 gallons of water). It seemed to get to work right away, watching the algae on the bottom bubble instantly. I turned the whole system on, so I let it run through the sump and back up. My only "complaint" is I still have to scrub. It softened it up, and in some spots it did flake off, but there are some spots, where it comes right off, but I need to physically touch it.
