Crazy Nitrates!

[xostrawberryox]

Hey all,

Last weekend, i moved my tank. We just took most of the water out and then moved the tank with the fish still in and then replaced the remaining water back in.
On Friday night i tested the water, ammonia and nitrite were 0 however nitrate was showing as 75-100mg/l.
Saturday I did a 25% water change. Tested in the evening and no change, 75-100. Sunday did a small 15% water change (i only had enough RO water for this and the LFS was closed) and then today I did a large 50% change, gravel-vac and cleaned the filter.
Left it to settle for couple of hours and then did nitrate test again and now it is slightly better, probably 50-75 now.
I'm really at a loss of what more to do? Do another 50% tomorrow?
Someone said that nitrate shouldn't be 0... so what should it be? S
The fish thats currently in the tank doesn't appear distressed at all and is eating healthy so I believe they have adapted to the water quality.
I currently appear to have a bit of a snail problem, could their waste be causing this huge spike?
Thanks

 

[WILDER]

What is your tap nitrate reading.
When did you last touch your filter sponges.

 

[xostrawberryox]

I don't use tap water, we use reverse osmosis water, should i test this??
I have a carbon filter with the white filter floss rather than sponges, i replace the floss about monthly i guess and rinse the carbon when i do a water change about fortnightly.

 

[andywg]

If you are using RO water, check the TDS of the "clean" water, the "waste" water and the tap water. If the TDS is nice and low on the clean water then the most likely problem is your test kit.

 

[xostrawberryox]

Right so i just tested the RO water from the remainder of the cannister i used for todays water change. It is prob about 15mg/l. So what should i be aiming for my tank's result to be and should i continue to try and bring the level down? Could a water change every day cause unnecessary stress to my fish? Not to mention having to buy the water every day!!

 

[andywg]

Go and buy a TDS meter and test your RO water. Fresh RO will not test right on nitrate test kits as there is nothing it it for the chemicals to react with (or at least there shoudl be far too little).

If you are using RO water and are having nitrate issues, the most likely outcome is that your nitrate test kit is duff (very few are truly accurate at the prices we pay, and some are just downright awful).

I have had nitrate kits test my nitrates as 160ppm in a SW miz that was nothing bu RO water and nitrate free salt. Similarly I had two samples taken from the same tank and tested at the same time come up as 0ppm and 160ppm. Don't stress about your nitrate readings until you get a TDS (Total Dissolved Solids) meter to test your RO water.