Coral-Only Tank Care

[less than bread]

So, unfortunately my reef tank is now a coral tank. The Ich got in and killed my fish. Played with fire by not having QT or hospital tank and got burned. So now I only have coral and assorted inverts in my 20 gallon.

 

I think I'm going to be okay since I still have to feed meaty frozen food to my nassarius snails (the same stuff I fed to the fish) and have been feeding reef roids to my coral so I should still have a decent supply of nitrate and phosphate. I will likely go down to 10% weekly water changes instead of 20% and will continue to test parameters weekly. Is there anything else I need to do to ensure my tank keeps on going with no fish in it?

[euphyllinme]

Are you going to just corals now or just going to wait until the ich is gone and put fish in? If just corals I would probably just go straight mechanical filtration and no carbon. Test daily and if you see a spike of nitrate/phosphate add just a little carbon to help. Ideally I would assume you don't want anything that would strip the tank of nutrients your tank would need to keep the biological filtration up.

[less than bread]

50 minutes ago, euphyllinme said:

Are you going to just corals now or just going to wait until the ich is gone and put fish in? If just corals I would probably just go straight mechanical filtration and no carbon. Test daily and if you see a spike of nitrate/phosphate add just a little carbon to help. Ideally I would assume you don't want anything that would strip the tank of nutrients your tank would need to keep the biological filtration up.

Yeah I'll definitely have another go at fish but I will be waiting at the very least 3 months before that happens. I'll remove the carbon I have to see how things react and sort of reevaluate how much/if any I need in this new environment. My nitrate and phosphate levels are pretty high right now due to a few months I was falling behind on water changes so I have been slowly working on getting those down anyway when the Ich hit. 

[jservedio]

I've kept coral only tanks and my current tank is extremely lightly stocked in terms of fish and the biggest issues I've always had is keeping nutrients up and keeping them stable long term. Feeding alone has never been even close to enough to keep my nutrients testable and I've always had to resort to dosing both N and P. Even with feeding two clowns and target feeding corals and nems, I am still dosing more than 1.5ppm/day of N and about 0.005ppm of P every day with zero chemical or mechanical filtration. It'd be even more P if it weren't for the fish food.

 

The lack of nutrients means you can feed more (potentially much, much more), but this tends to lead to other problems with particulate feeders (vermetids, colonial hydroids, etc.) and makes getting certain algae that can trap particulates like GHA very difficult to get a handle on. You may want to focus more on target feeding meatier foods that can be more easily cleaned up by crabs and nassarius snails and broadcast more sparingly.

 

You just have to find a nice balance between feeding and direct nutrient dosing - but once you find it, you are set for a very long time since you don't have fish growing up and changing the nutrient situation significantly. Corals change it as they grow, but not nearly as dramatically as fish do.