need help and advice

[Bilbo4fun]

55 gallon purchased used. 1 or 2' of crushed coral substrate (I didn't clean as tank was running) added 40 pounds of sand on top. 3 months later everything checks fine except nitrates 40 ppm. I removed bioballs from wet dry a month ago and at least 10 12 gallon or more water changes. Is it the old dirty crushed coral I need to get rid of?

Lost 2 clownfish 4 days apart. tore aquarium down today, removed live rock etc. they are nowhere to be found and dont see4 them on our floor? Ideas? they had been in tank for over 2 months and seemed fine. My blue and yellow tang seem fine. Could a clean up crew eat them that fast?
Thanks,
Gary

 

[chichimom79]

It depends on your CUC. Yes, they can be eaten very quickly. Sorry you are having issues. I do suspect the crushed coral.

 

[bjohanson1234]

I very rarely see dead fish bodies. The bristle worms eat it that fast. I believe that your nitrates are coming from over feeding and having fish that are too large for your tank. The blue and yellow tangs should really be in a larger tank.

The crushed coral is also an issue. Its large particle size catches large chunks of food which cause high nitrates. I would suggest slowly changing it out. But not too fast. Maybe a small section each month. That will allow the new sand to develop a bacteria population that will help with the nitrogen cycle.

 

[Bifferwine]

The problem with adding sand on top of crushed coral is that it's a smaller particle size, so it will eventually just make its way down between the crushed coral to the bottom of the tank anyways.

The crushed coral could very well be the culprit of the high nitrates, but so could other things:

Do you use tap water or RODI?
How often and how much do you do water changes?
How often and how much do you feed, and what kind of food?

And as BJ said, the tangs are too big for your tank.

 

[Bilbo4fun]

Thanks everyone. I think I screwed up by not tossing the crushed coral substrate and adding couple inches of sand on top of it. I've tried just feeding once every 3 days what they can eat in 3 mins. i use pellets. I've had saltwater tanks off and on since 13 and am 53 now. My last was a 40 gallon long and kept a blue tang for 4 years until moved from IN to SC. Still doing fine when I gave entire setup to my sons friend who would come over and watch tank for hours at a time. Just never had a problem with nitrates after cycle and water change. only lost 1 fish in all those setups so surprised me I lost 2 withing 3 or 4 days. Especially clown fish as they are hardy. I need to get the nitrates down from 40 as within a couple months (tank aged more) I want to start adding corals.

My only thought is to remove the 60 lbs live rock, remove all substrate, vacuum bottom and add new sand. Right or wrong?
Thanks again for all your help,
Gary

 

[SarahSmile]

Will you keep fish in there during the removal? Not a good idea for them, since levels will spike. Also, we don't encourage tangs (especially the ones you are referencing) in small tanks. There is always some story of it working out but 9 times out of 10 it doesn't and it's just not nice to the fish.

 

[Kelz88]

you can suck up the sand but you will have to do it a bit at a time if you dont want a cycle. However if there are no fish you could just do it all at once, add sand and let it cycle before adding anyone new