flu71

You will have to make a number of changes to get the nitrates down. Here's the hit list:

• Get rid of the wet/dry's bioballs - remove 25% of them each week for four weeks. This way your tank can adjust to the lack of that filtration.
• Get more live rock. 20lbs in a 90g isn't enough. You need between 90lbs and 140lbs to support the life in your tank via natural filtration.
• Do bigger water changes. Each time you change 50% of the water, you'll cut the nitrate in half.
• Get a better skimmer than what may have come with the wet/dry sump.

I hope that helps. Be sure to post some pictures of your fishies.

Might I add, bigger and more frequent water changes. In your case, weekly will be best and enable you to get an upper hand in the matter.

Thanks for the help,

Melev, I will remove the bioballs, and there i will put a refugiom with substrate an live rock, I will increase the amount of live rock on the system, can you recomend a insump skimmer?

Also i started to see some king of brown algee with fine hair on the substrate ( crushed coral) High levels of nitrate could be the cause?

What water source are you using? Tap or RO? My city water has 10ppm nitrates out of the faucet. I installed a RO/DI unit less than a month after I got into the hobby. It's well worth the investment

Crushed coral is another nitrate trap, because the detritus collects within it. I had CC in my 29g for all seven years that that tank was running, and about three times a year I would use a gravel vac to siphon out all the detritus I could. It's pretty disgusting when you see ( and smell) how much comes up.

You only have so much room in your sump, so perhaps the Aqua-C Remora Pro would be best. It doesn't take up much room, and should handle that much water.

I use RO water, Im thinking to add a DI unit, but for now im using only RO water ..

Melev, talking about the subtrate, it is ok? if i use cruched corrals? or what kind of subtrate you recommend?

Thanks for all the support, I did a lot of reading but when it came to the real thing i dont want to make a mistake...

The Fish i have r..

1 FoxFace
1 Yellow Tang
1 Sail Tang
1 Fire Shrimp
1 Damiselle
2 False Precula fish
1 Scopa Tang ...

I will uploading photos soon!!..

Thanks..

You have 3 tangs and a Foxface, which is a significant bioload on your tank. Even if they are small now, they will grow. The food they need will definitely add to nitrate (NO3) and phosphate (PO4) issues on a continual basis. The shrimp isn't an issue, and the smaller fish aren't a concern either (even when full grown).

CC is appealing to look at and won't move, but it traps waste like a fly to flypaper. Switching over to fine sand would be better.

not to hijack the post, but I figured here is a good spot since it's on topic, but how do some of you guys keep your sand looking so pristine? Do you have to use any type of vacs on it or do you just have a sufficient cleanup crew to keep it spotless?

Good flow and a clean up crew usually keeps the sand looking nice. There are times when it will look dirty, but that is usual rather than common. If the sandbed is healthy with live bacteria, that helps. Fighting Conchs and cucumbers as well as hermits and nassarius snails keep it turned over and clean.