This is my second season owning a pool. Last year, I had a pool guy. At the beginning of the year I got rid of him and am all in on the TFP method. It seems to be going well (even if the pool guy left me with higher CYA than I'd like). I'm trying to figure out how to properly disassemble/clean and refill my filter with DE. Sorry for the long story that follows, but I want to learn...
I just took the one-year-old Pentair FNS Plus 48 DE filter apart, sprayed it off, and put it back together, carefully following instructions, coating the gaskets with lubricant, etc. I started the system back up at full speed, made sure there was no air in the filter, and then dumped a 5 gal bucket of water and 4.8 lbs (I measured with a scale.) of DE into the skimmer. Immediately, clouds of DE came out of the jets. I figured that wasn't supposed to happen.
I took the filter back apart, and saw that DE was only coating the top four inches or so of the grids. I cleaned them off more carefully and fully inspected everything afraid I was going to find something broken. Not so. Everything looks good, almost new--like I'd expect a one-year-old system to look. No visible damage at all.
Here's what I assumed happened, but I'd appreciate some help understanding. I read the filter manual before I did anything, including the part where Pentair warns not to let the pump run for more than three minutes without DE in the filter. So, I concluded it would be best to run the pump at full speed and dump the DE in as fast as possible once I started it back up. I have since read advice saying to add it slowly. Somehow adding the DE fast must allow it to bypass the filter grids and blow right back into the pool? Is that right? It doesn't make sense to me that the water can bypass the grids, but it's the only thing I can come up with.
After cleaning the grids a second time, I put everything back together again, then, while running the pump at my usual slow 1100 RPM/22 GPM, I added the DE very slowly, over the course of several minutes. I didn't see anything coming out of the jets (but I figure I wouldn't have either way, given how slowly I was adding it). I'm assuming all is well inside the filter this time, and that it is just a matter of time--swimming, brushing, running the cleaner robot--and the DE that got blown into the pool will get captured by the robot or by the filter.
How am I doing figuring this out? Obviously, I could take the filter apart a third time to see if I've figured out how to do it right, but I don't have any more DE, and with the whole COVID-19 situation, getting more is a hassle right now.
I just took the one-year-old Pentair FNS Plus 48 DE filter apart, sprayed it off, and put it back together, carefully following instructions, coating the gaskets with lubricant, etc. I started the system back up at full speed, made sure there was no air in the filter, and then dumped a 5 gal bucket of water and 4.8 lbs (I measured with a scale.) of DE into the skimmer. Immediately, clouds of DE came out of the jets. I figured that wasn't supposed to happen.
I took the filter back apart, and saw that DE was only coating the top four inches or so of the grids. I cleaned them off more carefully and fully inspected everything afraid I was going to find something broken. Not so. Everything looks good, almost new--like I'd expect a one-year-old system to look. No visible damage at all.
Here's what I assumed happened, but I'd appreciate some help understanding. I read the filter manual before I did anything, including the part where Pentair warns not to let the pump run for more than three minutes without DE in the filter. So, I concluded it would be best to run the pump at full speed and dump the DE in as fast as possible once I started it back up. I have since read advice saying to add it slowly. Somehow adding the DE fast must allow it to bypass the filter grids and blow right back into the pool? Is that right? It doesn't make sense to me that the water can bypass the grids, but it's the only thing I can come up with.
After cleaning the grids a second time, I put everything back together again, then, while running the pump at my usual slow 1100 RPM/22 GPM, I added the DE very slowly, over the course of several minutes. I didn't see anything coming out of the jets (but I figure I wouldn't have either way, given how slowly I was adding it). I'm assuming all is well inside the filter this time, and that it is just a matter of time--swimming, brushing, running the cleaner robot--and the DE that got blown into the pool will get captured by the robot or by the filter.
How am I doing figuring this out? Obviously, I could take the filter apart a third time to see if I've figured out how to do it right, but I don't have any more DE, and with the whole COVID-19 situation, getting more is a hassle right now.
