Need help on filter size - Replacing my Hayward filter

[mcdickey]

I have an 18,000 gallon salt water pool/spa that has a cracked Hayward S311SXV sand filter (side mount) that I need to replace as soon as possible. According to Hayward, this filter has an effective filtration area of 4.95 ft. and a design flow rate of 99 GPM. I would potentially like to replace the filter with a Hayward S310T2 sand filter (top mount) that has an effective filtration area of 4.91 ft. and a design flow rate of 98 GPM. I know I will have to re-work some plumbing to convert from side mount to top mount, but other than that should I be OK given the similar/same specs between the two units?

FYI. I am considering the change in model due mainly to price.

 

[jblizzle]

A general recommendation for filter size for you size pool would be a minimum of 3.3 sqft (25" diameter). Since we stay open all year, going a little larger may reduce the frequency of cleaning it. Although you may not need to go all the way up to a 31".

How often are you backwashing it now? We recommend doing so when the pressure rises 20-25% over the clean pressure. Honestly, with a filter that big, I would be surprised if you have to backwash more than 1-2 times per year.

 

[mcdickey]

Thank you for the recommendation. I actually changed gears and decided to get away from sand and switched over to a DE filter. I went with the Hayward DE6020 model (60 ft2 filtration area and 150 GPM design flow rate) and am excited to see how much of a clarity difference the DE makes versus my current sand filter. I expect the new filter and DE media to be delivered on Friday and, if things go well, I'll be up and running on Saturday.

In response to your question above, I have been backwashing about once every two months when the pressure would rise as you stated above. My pressure after backwashing is about 18 PSI and I backwash again at about 22 PSI.

Thanks again for your help.

 

[duraleigh]

We talk about this all the time on this forum.

If you are switching to DE to see improved clarity, you may be disappointed. It's difficult to tell the difference.

What does your water look like now?

 

[mcdickey]

Thanks to TFP my water looks good in the day, but at night with the pool lights on you can definitely still see floaties. I am also not switching to DE JUST for clarity, but that is one of the reasons for the change. My sand filter broke and I can get the DE filter for not much more $ than a new sand filter. I am also interested in DE because of the longer cycles between backwashings and overall cleaner water.

 

[jblizzle]

I still see tons of floaties in mine at night ... hard not to with all the dirt and dust around here.

DE are a little more work and like Dave said, do not have too high of expectations.

Not sure where you go the longer cycles thing ... if anything comparably sized DE might have shorter cycles due to being more efficient at grabbing stuff.

A big enough filter of any kind will require very few cleanings. The one you got should work well. IIRC, I don't think I backwashed more than 1-2 times all last year (and maybe not even that much). Although I do not use a suction cleaner which will require cleaning the filter more often.

 

[mcdickey]

Thanks Jason. I am comforted to see that you have about the same size pool as I do and live in Tucson and have the Hayward 6020 DE Filter. If it is working for you I am sure it will work for me.

BTW, I got the longer cycles thing mostly because of the increased filtration area.

 

[jblizzle]

Looking back at my records, I listed backwashing in May 2013 and then I did a full filter breakdown in April 2014 ... I can not remember if I backwashed between then or not. In any case, the filter should work well, you just might need to clean a little more often due to the suction cleaner.