edikpok said:
I perform constant water changes buy the nitrate level is still high. What product is the best to use in order to minimize my nitrates level.
Instead of treating the symptom, look to the source. Your system is a bit overcrowded, more info below from my files:
High nitrates are more of an indicator of total dissolved organic compounds and overall system health, such as PH issues. Some species are indeed less/more sensitive than others to DOC's and nutrient/metabolite buildup. For reef/invert systems, most target less than 5 ppm and they often keep sparse fish populations in those tanks to help limit nutrient input. For more robust fish systems nitrates are less of a concern; a 20 to 40 ppm reading is common and can usually be maintained/lowered with efficient skimming and scheduled water changes. While many fish are likely not harmed by moderate or even higher nitrate levels, IMO higher nitrates almost always go hand in hand with a low PH; and PH/alkaline reserve is a much more serious parameter that requires careful attention in all marine systems.
Well the first thing you need to do is verify your readings with another test kit. Have your LFS check the water.
Providing your readings are accurate I would say:
1. Large bio filters, trickle towers, cannisters are not helping, the media is going to convert any nutrients to more nitrates. We don't need more CONVERSION here with your light bio load, what we need is more nutrient EXPORT. I would SLOWLY remove this media in both of them over the period of 90 days, a little at a time. Leave the cannisters running empty for more circulation.
2. At the SAME time, add a powerful skimmer. Also make sure your skimmer is working; should be removing dark sludge every day for you, if not then adjust it or find one that does. If one is not doing the job you can add another unit, but always start by getting one bigger than the gallon rating on the box. Choose wisely, lots of overated junk out there.
3. Tell me about your substrate; 2-3 inch crushed coral beds, dead sand beds in robust fish displays can all be nutrient sinks/adding nitrates faster than water changes can keep up. Hobby is supposed to be relaxing, after all. A properly balanced basic marine system should only require monthly water changes or less.
4. You may need to look into a deep sand bed (DSB) located inside a refugium (not in the display) there is much info available on the web for that, use your search engine. Also look into an algae filter, which can also be located in a refugium/sump below the tank. Try a big wad of chaetomorpha (not caulerpa) in a reverse lighted sump, that will serve as a great export filter for your pesky nitrates. Plants love consuming fertilizer! Be advised, you don't need zero readings for a basic FOWLR system, but agree 100 is too high.
5. Lighten the load! Less is more... less food, less waste, you get the idea. Less fuel for the fire so to speak... stop asking, "how many more fish can I have," and instead ask, "how few fish can I be happy with?" Those few carefully chosen specimens will be more healthy and even have room to grow. Best wishes for your success.