1. Well you can move the fish before or after taking out the river rocks, i would recommend before so they dont have to undergo even more stress. Move them into a Rubbermaid bin, or another tank with an airator(they will be in here for at least 2 hours).
Turn off your filter at this time.
2. Remove all the rocks.
3. Syphon/clean out all the gunk that was under the rocks and on your glass now
4. Clean out the sand by washing it in 5 gallon buckets, do a bit more than half a bag at a time, and make sure to stir it until the water comes out clear. To be more specific run a hose over the sand in the 5 gallon bucket in your shower or outside and stir up the sand. When you first put the hose in the water should come out murky due to dust in the sand and other particles. Once you have stirred the sand for 2-3 minutes it should be crystal clear water coming out of your bucket.
5. Put the sand in your tank.. Dont dump it in there, try to use something that will allow you to gently place the sand on the bottom.
6. Repeat steps 4 and 5 until all the sand is in.
7. Allow about 30 mins for the sand to settle a bit.
8. If the water is still cloudy do a 50 pct water change and make sure when you are putting new water in, to use a bowl or your hand as to not disrupt the bottom, it will be defeating the purpose if it does.
If not, check the water parameters and put your fish in by acclimating them and turn on your filters. Pool filter sand WILL NOT go into your filters, so no need to worry.
There ya go. Dont expect the water to be crystal clear even if you do the 50 pct water change, just try for you to be able to see through the tank at least to the back of it then it should be safe to put the fish in. Once you run your filters, the next morning should be alot better, and by the second day should be back to normal!
