I moved my 30 gal tank about a month ago. I saved 25% of the old water. Since then the water is a foggy green color. I do a 25% water change once a week and tthe water is clear for a few hours then back to green. I have run every possible test on the water and all checks out ok. Does anyone know what causes this. :huh:

If it's green, it sounds like suspended algae. I sometimes get that in my 65 gallon tank with three small fantails and my 15" pleco. Suspended algae will grow in a tank when there is sunlight hitting the tank, excess food, and/or a lot of fish waste. Often, a larger tank or filter solves the problem. If you can't reduce the amount of food or fish, then you can try some temporary fixes. I've used pond AlgaeFix in my tank when I do my weekly 50% water change. The next day, it's totally clear, and that lasts for two weeks or more before I might need another dose. AccuClear is another chemical that can clear up algae in the water but it's very temporary and may only last a few days. It basically causes particles in the water to clump out and sink or be filtered which means the algae can just grow back as soon as that's done.

What animals do you have in the tank? Does sunlight fall upon the tank any time during the day?

My aquarium algae page is at http://www.fishpondinfo.com/plants/algae.htm and includes a section on cloudy and/or green water and suspended algae.

I did a 3/4 water change and changed all filter media yesterday and it is still clear today. I also plan to keep the blinds closed on the window nearest the tank. There was no direct sunlight hitting the tank but it is closer to a window(LIGHT) than it was b4.
I call this tank my odd tank because the fish i have in it should in all reality not be together,,but they have all been together for over a year and so far no problems. In the tank i have 1 4 inch parrot cichlid, 1 41/2 inch yellow lab cichlid, 1 2 inch spotted green puffer, 1 3 inch angel fish, 1 6 inch pleco, 4 rosy red minnows(3 babies and 1 adult) and about 10 assorted tetras. :o I really hate to add any sort of chemicals except dechlor unless absolutly necessary. So i will see how it goes for a while. My first thought on the matter was that i killed my bio-wheel when i moved the tank. I dont know,,any added thoughts would be great. Oh yea i also have an adult male albino Paradise fish in there also. :lol:

Sometimes indirect sunlight can also cause an algae bloom. Just moving the biowheel shouldn't have killed it off.

Your tank will soon become crowded as those fish grow. Your problems may also grow as you definitely have a "no-no tank." I have my own such tank with land animals. It's a 20 gallon with two green anoles, 14 six-spotted roaches, crickets, mealworms, and now a hermit crab my mother bought on impulse (bad!). A few people yelled at me that it couldn't be done but the animals don't bother each other at all. Last Sunday, I put a 4" high divider in and made about 35% of the tank sand and hermit crab soil with the rest the way it was with Repti-bark. Did Herman enjoy his new "followed the experts directions" tank? Nope, he keeps climbing to the roaches' side! I keep putting him back. He doesn't want to play in the sand!

Yes it is a no no tank. But all the big fish( the 2 cichlids, angelfish, pufferfish, pleco) have been together since they were babies (Got them all the same day) and i have never seen them fight or show any aggression twards each other. They have been in the same tank for 18 months now. I do plan to keep them all together and eventually move them to a 55 gallon tank, and then move the 4 fantail goldfish i have in a 12 gallon tank into the 30. I have a small apartment in N.Y.C./Bronx so i cant have as many tanks as i would like. And yes Robyn i have learned to do a bit of reserch b4 going and getting a bunch of fish that dont belong together. I got lucky with these guys but probably would not be that lucky again. I love your site here and wish i would have known about it before i started the hobby. Over 24 hrs and the 30 is still clear,,,yea :D