the nitrate plague, HELP AGAIN!!

[holley]

My nitrates will not go down no matter what I try. I have changed 5 gallons of water on a weekly basis, however the Nitrates never go below 140ppm.
I have a 75 gallon tank that has been up and running for 5 months with the following features:
 Tide pool wet dry system, (bought this one month ago on Beth’s suggestion to get ride of the canister filter).
 Protein Skimmer
 Two heaters
 70 lbs. of LR
 3 inches of DSB
 power head
 Good twin bulb lighting
 I change at least 5 gallons of water ever week with RO/DI from Krogers. (Never miss a week).
 The feeding is sparse, once a day, (they eat the food in less than one minute).
 I have 2 small tangs, 1 small box fish, 1 small damsel, 1 small clown fish, 1 cleaner shrimp, 1 star sifter, 1 small scooter benny, and 3 anemones.
My water conditions are perfect except for the nitrates. My LFS is trying to sell me an UV filter for a 300-gallon tank.
1) Will this UV filter lower my Nitrates?
2) Should I purchase this filter regardless?
3) Should I starve my fish more than I already am? (This part bothers me).
4) I am doomed to high nitrates forever, and I should just except it?
I want my water conditions perfect please help me get the nitrates under control. All my fish are fine except the tangs. The tangs are showing signs of fine rot but it seems to be turning around. I have written this site three times on this matter and each time I have taken your advice. Once again I am seeking help from the experienced.
My motto is;
Know you limitations
Know when to ask for help
Expand your limitations until you have none!
Thanks,
Jack Holley

 

[jakob4001]

you may want to change out 10 gallons; you can also buy nitrate sponge that may/may not help; UV filter will not assist in nitrate problem; does your wet/dry have a skimmer? that might help...
we used EHEIM canister filter for the 135 w/ carbon 24/7 & various filter media in it w/o water problems being q tip sponges seem to thrive & flower pot is doing very well

 

[puff(er) daddy]

I've tried everything in the book to remove my nitrates and it haven't improved yet. I don't recommend the sponge until you know the source of the problem. I narrowed mine down to me having a very big messy fish that exceeded my bio filter and when I first filled my tank it was with tap water. I later tested the tap water I was using and the nitrate reading was < 20ppm, if I rememmber correctly.
It's a process of elimination and your on the right track just keep testing and maybe increase your w/c amount to 15 to 20 gallons. Just make sure it's the same temp., salinity,and all the others since you have fish in there, I traded mine in to see if it was the problem. It wasn't.

 

[tiggerbengal]

Do you have bio-balls in your wet/dry by any chance? If you do, try taking those out to see if your nitrates lower. I had a canister on my tank, and ended up ditching it because of the excess red slime, which is caused by nitrates. I know that since taking it off, I have no more problems. I also increased my sandbed from 1" to 4". Maybe add another inch of sand?

 

[diatom]

Well I can think of a ton of things to do some will help others might.
Lets start at the bottom:
1. the wet/dry. I believe it has a biowheel...removing that should help.
2. Your DSB is to shallow...add an inch to it...then in a month add another inch.
3. That sand sifting star is decimating the creatures in your sand bed that allow it to function properly. Bye bye. Also your sand bed will need to be reseeded.
4. have you tested the Water from Krogers? Their filters might be outdated and their water may not be any good.
5. You need some nutrient export...adding a light a light and some macro algae to that sump should help.
Try these things and do a nice size water change and lets see what happens in 3 weeks or so.

 

[crystain]

You may also want to clean any filter media you have (if any). They tend to "crud" up with detritus which then decomposes.
I agree with the macro algae suggestion. Possibly even in the show tank. I have some calurpa growing in my tank and its easy enough to reach in a grab a bunch. Ah yes. Nutrient export.

 

[holley]

I understand the math behind dilution, and I will increase the amount until under control. However, I thought the system would take care of itself without all this extra effort to lower the nitrates.
I do not have bio balls. The Kroger's water tested OK. I will increase DSB.
Do I really need to get rid of the star sifter?
Should I really remove the bio wheel, and if so for how long?
Please explain what this statement means in layman's terms and where I can get such an item, (You need some nutrient export...adding a light and some macro algae to that sump should help).