Cant lower Nitrates cant keep Ca levels up??

I've been really testing my water recently and noticed that nitrate levels were about 20 ppm. So over the past 3 weeks I did three 5 gallon water changes with RO water, really vaccumed my substrate, and cut back on feeding. I retested for nitrates today and still got a reading of 20ppm. I know the problem isnt my test kit because I tested the water at the lfs and got readings of 80ppm (really bad). Any advice on how to lower nitrates.

Also I cant seem to keep my calcium levels up. I have to continuly add calcium to the water to get at least a reading of 420. I cant seem to keep it stable. I think I may be starting to grow coralline algae and thought may it be could be consuming the Ca not sure. But any advice on how to stablize calcium levels??

thanks

 

Do you have the bio wheels on your filter if so take them off

 

Also what is your mag and dkh at? you need to have them balanced as well to balance cal.

 

Yea I removed the bio wheel awhile ago becase I read they could add to nitrate problems. I have a fuge with some macro (dosent seem to grow) but is dosent do much. As for mag and dkh I know I should probably test for them but i figured because I was getting some coralline growth they were pobably in check but Im stating to think I should test them.

thanks

 

Your mag is most likely of you do need a test so you will know what to do. And how old is the tank

 

20 ppm really isnt that bad.10%. i do weekly water changes of 10%. also i wouldnt sugges how often do you feed and do water changes. ur water changes of 5 gallons for three weeks really wont do much. thats a little over 10%. also giving the gravel/sand a really good cleaning, isnt the best idea imo do a section each month with water changes and do the next part next time. also what test kits are you using?

 

The tanks about 9 months

Also I am using the API test kit. The reason Ive really been cleaning the gravel is Im afraid that the DOC that accumulate on the gravel with cause my phosphate levels to rise.

thanks

 

I agree

 

+2 on RedMans comment.

 

As mentioned above I would test DKH and Mag. full breakdown on what is in your tank i.e coral type and fish. What type of salt? Test it and see what it's level are it first. What are your supplementing with?