I do not know how old your tank is, but sometimes small particles floating in the water could air bubbles from the aeration of the filters and air stones. So do you have heavy aeration?

If so, you can pull back on the aeration. But you do need good areation for the gas esxchange at the surface will convert into oxygen for the tank.

Another scenerio, could you tell me if the smal particles are white? If this is the case, it could be white worms having been stirred up during vacuuming. These things are harmless. You will need to take out all your fish from the tank, raise the temperatuve to 90-95 F to kill off the worms. Then wait a several hours to bringt he temp down, and put your fish back in the tank.

Another scenerio which I think is the problem, or most likely the problem (just like the other member's post (confused newbie...by kimberhugo), of course, this relies upon how old your tank is, but if the tank is new, say 2-4 weeks, then you may be experiecning high nutrient levels in your tank.

Nutrients comes in our tap water (supplied by the water treatment plants), if there is not enough good bacteria (nitrate) to consume the nutrients, the nutrients go skyrocketing (anytime you do a new water change, you put high nutrient levels into the tank), the nitrate can't keep up with all the new nutrients, and you wind up with white fuzzy stuff all over the place plus your water is not crystal clear.

The cure for this is, as time goes by, as the nitrate or good bacteria builds up, it is able to consume more and more of the nutrients thereby the water becomes clearer and clearer.

Another scenerio is, do you do deep vacuuming during a water change, because if you do, you take out good bacteria in a newly set up tank, and again, any nitrate is not plentiful enough to consume the nutrients.

Do not put any chemicals in the tank. I frown upon chemicals. In time, the tank will adjust as long as you take the above-listed precautions.

LIve plants also consume nutrients, so it is good to get live plants.

Also, do not overfeed, this causes too much waste and in a new tank (and even if it is an old established tank, though it does not happen quickly like in a new tank), the bioload or the nitrate is unable to feed off the leftover debris or waste which causes srious problems in the tank to the point that this will kill your fish.

To solve this problem, you can get Olive Nerite Snails (these little guys, I have 35 of them, eat algae, debris, etc), ghost shrimp (they do the same as the snails...and by the way, these Nerite snails, their eggs to not reproduce so you won't have a huge snail explosion). Just do not put copper into the tank, snails and ghost shrimp or invertebrates do not do well in even small concentrations of copper (though a trace in such a large tank of yours probably will not harm them). But these little guys will consume foods that can spike your nitrite and ammonia.

nitrate at 20 ppm is good. your tank being large is even better. you will find in this hobby, that if you hang with it, in time, the ecosystem will develop to an established tank. IN the fish hobby, we all strive for a balanced ecosystem as in the wild.

if you have any questions, please do not hesitate; there are very knowledgable members in this forum, I am sure you will get other suggestions too.

Could you provide me with how old is the tank and if you have any live plants?

hope this helps

if its just air bubbls floating i woudnt care honestly but thats just me. If i can see all the way through my tank any way i look at it im happy.

I thought API stresscoat is dechlorinator

API stress coat contains dechlorinator.

white particles? Now we're getting somewhere

white particles happens during a bacterial bloom. After the fish tank is cycled, it could be several weeks later, bacterail bloom can occur. IT is harmless to the fish even though it is unsightly for the fish keeper.

Bacterial bloom occurs when there is excess food waste, debris in the tank. It accumulates over time.

First thing that should be dowe is cut back on your feeding. For one week, just feed the fish every 3 days. Every Sunday I give my fish absolutely no food. It helps to clean out their digestive tract plus it gives the filters a rest. Clean as much as the debris you can from the gravel which may make the tank a little cloudier, but once it settles, your tank will be for the better.

There is really nohting to be alarmed about. IT's just an over-abudance of bacteria in the water column.

I agree with peter, even though 20 ppm is a moderate level, it is best to stay with 10 ppm and below. IT's okay to have a little nitrate in the tank. But if you let your tank get to 20 ppm and upward, the fish start to really stress, and if it reaches to 40 ppm (though some sources say this is okay), I completely disagree for at 40 ppm, you will stress the fish so much that they will have less immunity against illnesses or bad water conditions or even bacterial bloom. 40 ppm can kill a fish. 20 ppm will stress a fish especially a weak one. 10 ppm is safe and 5 ppm is best

anytime the nitrate level goes over 10 ppm, do a 20% water change

the white partciles or bacterial bloom will go away on its own though it can be helped with a vacuuming; there will be less gunk in the water column if you do a vacuuming; if you just leave it be, the partciles will either settle into the gravel or be sifted through the filtration. These are choices you must make as a fish keeper.

hope this helps