[AquaticLife] Problems with Nitrates and pH.
From your ammonia reading, your tank is still cycling, and has not yet reached equilibrium. When you start getting 0 for your ammonia reading, then you can start to worry about your nitrate levels.
One place to look for nitrates is in your tap water. Test it and see what the level is there. You should test it every so often, as the level can vary depending on the source of the water, the method of treatment, etc.
A water change will not remove all nitrates, only a portion of those present above the level found in the water used for the change. You currently are measuring 80 ppm. If your water has 0 ppm and you do a 25% water change, you can expect the water to show a reduction of approximately 25%, or go down to about 60 ppm.
I do find it a bit strange that you have an ammonia level and a nitrate level, but no nitrites in your water. It is possible, but not likely. Check the expiration dates on your reagents to ensure they have not expired. No expiration date? Change brands to get one that does give you expiration dates.
Water chemistry is water chemistry. I say that because I am not a marine guy. I do understand from what I have read/heard, that once your live rock cycles, it will help maintain a low nitrate level.
\Steve//
Category: Philippines Internet Koi Society
