Thanks-- I went to the pool store & picked up the G4 & it does fit like a charm. My G3 was round in the center also but it is a few years old maybe they changed the newer G3s to octagon. I did see some of the octagon ones in the internet so I was a little confused. But anyway problem solved thanks for looking into that for me.

Thanks to everyone for your advice! Lindsey - When I soak the cartridges, is there a cleaner, or some solution, that I am suppose to soak them in? Also, what do you use to soak them in? The filters are about 3 ft. long. Florida gal - For all I know the PB may have told me to clean the filters sooner. My head was spinning when he gave me the "Pool 101" class. I'm glad I checked here. This site has been a great source of advice. Yes, there are 4 cartridges inside the filter tank. I was actually suprised myself. I was expecting to see one large filter or something (remember, I'm a first time pool owner). By the way, your pool looks awesome! I love the landscaping. This is the look I am going for around our pool. We haven't started planting yet, but we want a tropical look. When I figure out how, I will post some pictures. gk - I think you are right, I should probably try cleaning it again after a few days. I imagine there's still a lot of junk in the water that still needs to be filtered. Again, I thought they said every 3 months, but I may have misunderstood (wouldn't be the first time!). They may have said every 3 weeks. The PB did a great job and seemed to know his stuff. Thanks again to everyone for your help.

Need more information to answer your question. What part of the country are you in? What type of Jandy pump is being used?

daisee86 I live in Denton. There are a couple of test that you can do to determine if the pool is losing water. Mark the water level along the tile line 24 hours later return and measure the water loss. You can also do what is called the bucket test. Fill a bucket and place it in the pool like on a step or bench. Mark the level on the inside the bucket along with the pool level on the outside of the bucket. 24 hours later return and measure the water loss in both the bucket and on the outside of the bucket. If both have lost the same amount then no leak is present. If pool lost more than the bucket then you need to have someone check pool with more advanced test. In our area it is not uncommon to lose 3/8 to 1/2 per day. Endure can be added at any time as it does not evaporate and can only be lost through backwashing, splashout or leaks. So I would wait until you determined if the pool is leaking. Cheaper is not always better. I would recommend using a pool store that you fell comforatble with as they can offer much more than many of the big box stores. You can check out the following website for more helpful information. www.gohlkepools.com Hope this helps