As usual, excellent & accurate info coming from Bill Cody! First and foremost ~ do not inadequatly aerate your pond. It's better to not aerate at all than to do it half way. If you under aerate, all you are doing is mixing the bad bottom water with the good upper water and making it all bad. The fish will have no chance. Especially if you are talking about 25' deep water. Second, you have to have a compressor that can handle the pressure needed to pump air 25' deep ~ you will need a compressor that can handle 15 PSI. 20' of pipe with large holes will not be effective in creating a vertical column of water large enough to circulate the pond water volume once per day. If the holes were small enough to create micron size bubbles, it would require a LOT of cfm. Aeration companies have been doing the science for years, figuring out the most efficient and cost effective ways to aerate ponds, so the best thing to do is to consult with an expert to determine what your pond needs. You can take it from there~
