Should I remove my shallow sand bed - issues in tank

[Myka]

I use vinegar in kalkwasser and add it through a doser. I don't use it for nutrient lowering reasons, I use it to make the kalk more concentrated. It definitely affects the PO4 and NO3. That's an option too. I dose BioDigest as well. Biopellets I think are simpler and easier for long-term.

[corpusse]

More interesting developments : I haven't really touched the tank this week, been occupied with the blue jays however cyano seems to be getting worse. That being said tests indicate a phosphate level of 0.02 (lowest test yet) amd nitrates somewhere along the 5ppm also lowest. I did lose one blasto colony but blastos can be touch and go at the best of times and it's been months since they have been fed.

I was about to test newly mixed water with tank sand to see if its a nitrate source but first I figured I'd test the water and much to my surprise my newly mixed water is testing at 2ppm nitrate! I use 55g barrels to mix my water I'm guessing there is just a small amount of organic matter from reef crystals salt causing this. I used to use one barrel for freshly mixed water and one for the old water I'd recycle to my other tanks. These days I need so much water I use both for mixing new water. I tested the fresh RO/DI water in the other barrel and it came back at 0. I do wipe the barrels down but they do not always get a super crazy cleaning since it's just fresh water salt and a powerhead going in them. It's possible the crud on the powerhead is the organic matter causing the nitrates. This doesn't solve the tank issues but does help explain why large water changes are not eliminating the problems.

Finally despite not adding anything but nopox my skimmer is skimming out almost black skimmate which is why I have not taken it offline to run chemiclean. That being said I still consider it an option if nitrates and phosphates do not increase in the next 1-2 weeks. I will make water in the barrel testing at 0 nitrates with ro/di and then test that water as well.

I still plan on removing some of the rock and perhaps increasing the flow. It does look like there may be some light at the end of the tunnel but I don't want to jump to any conclusions. Biopellets will likely eventually be added too. Then I can probably feed the tank again.

[corpusse]

Only another week to go until the fish go back.

I removed some rock. Interestingly the rock itself has some cyano growing on it in a 10g tank with one tiny powerhead. I have continued to dose nopox as if nitrates are greater than 10 although more likely they are 5-10ppm these days. Phosphates tested at 0.03 yesterday which is great but still a tiny bit of cyano on the sandbed. The I have removed some of the sand cleaning the tank weekly or twice a week. Going to try just a few more big water changes then the fish go back.

Looking forward instead of or in additon to bio pellets I am reluctantly going to start replacing my live rock. I'll pick up say 50-75lbs of dry pukani and then cycle / cure it separate and then just start replacing the rock. I'll try and get rid of the clove polyp infested rocks as well as the rocks that grow algae on them however many have corals encrusted. I may have to just break them up and if I lose a few pieces so be it. I know they say nitrates cannot bind to rocks but I really have a hard time beliving that these days. I've changed so much water. removed so much from my skimmer and only fed the tank once in 70 days yet I still have both nitrates and phosphates. They are now at basically acceptable levels but thats without feeding.