Nitrates spiraling out of control

I have read on here many cases of tanks parameters all of a sudden turning. I guess it's my turn..

The Nitrates spiked to 50...so I did what I thought was a large water change (15 gallons) and cleaned the sump out since it was pretty nasty.

I had it tested Friday ( a week later) and low and behold... the nitrates were at 100.

PH dropped to 7.6
KH was at 9
and the salinity was lower than I thought 1.020

I did a 35 gallon water change and added a buffer yesterday. My fish all survived so far.

I retested at home and the nitrates, although lower (hard to get an exact on a color card) at what I estimate to be 40 are still too high. The PH did balance out at 8.3, and the KH was 12-13.

Is there a chemical that I can add to help stabilize the nitrates? Or should I just hope for the best?

The only thing I can think of that could have happeded here is my missing Wrasse may have died... but I vaccumed and found no sign of a carcass.
I was told by the LFS child that he had one that hid in the sand bed for almost 3 months and then appeared when the water stabilized.

If he was in the sand bed... he ain't happy.. I really messed up the rock and sand work with the vacuum.

I have given up on the Wrasse at this point.. I am trying to salvage my remaining inhabants.

What now?

 

Well its not the wet/dry many want to call a nitrate factory. stirring the sand bed ? how old is the tank 2.5 maybe 3 yrs or so.. How much sand and what do you have i there to keep it sifted out ? Ever considered using a coil denitrater ? they do wonders long term and cost nothing to run and cheap to make . Maybe thats why not many speak of them ? It could be OTS staring to rear it head ? OH OTS old tank syndrome. With falling Ph and low buffering abality of the water

 

I have always been schooled that it is not so much the wet/dry that is the nitrate factory - but the bio-balls that are used in them. I replaced the bio balls with live rock al ong time ago.

My tank has been set up for7 months total.
What is involved in making a coil denitrater? Do you have a link I can follow?

 

Huum at just 7 months you should not have a problem with them As for the rocks in a wet /dry ? The balls break up the water more and allow for a richer 0'2 enviroment.. I found that lots of air in the sump will also help keem the fom the water as it will with PO4's I think I posted a a simple how to But I was thinking about writing the instructions down I had done this once but its on another computer on my desk at home.. Its really easy to do .. I'm sure there is some info around the net ? Nitra-Gon used to sell them also..

 

put chemi pure in your filter. It worked wonders for me!