intelliflo and hayward filter matchup help

[mas985]

Have narrowed down to the Intelliflo and either a sand or d.e. hayward filter. I have d.e. now and hate cleaning the thing. My question is, if I get 21" sand filter, it's rated to 44 gallons per minute. Do I have to match up the filter/pump GPM even though 90% of the time the pump will be operating at a much lower level? I'd only go above 44 gpm when backwashing or using the spa to get the jets going. Is that going to stress out the filter?

The ratings stamped on the side of a filter are usually ANSI/NSF 50 ratings and are based on proper filtration of the water. So if you were to go above that, it just means the filter is not filtering as well. If the flow rate got too high, then there is a good chance that the filter could be damaged but I couldn't tell you exactly what that flow rate would be. But keep in mind that there are a lot of benefits to going with a larger filter. Better filtration, longer time between cleanings and for a sand filter, lower head loss.

Have you considered a cartridge filter? There are several reasons I would recommend a cartridge over the other two for a southern California home:

1) No backwashing. A small sand filter will require frequent backwashing which will use a lot of water and since you don't get much rain and the price of water is increasing here in CA, this could save you some money in the long run.

2) No backwash valves. Most backwash valves have a lot of head loss which will reduce your pump efficiency and cost more to run.

3) If properly sized, you may only need to clean the filter once a year like I do. This will save both time and water.

Most people who don’t like their cartridge filter have one that is way too small for their pool so they end up cleaning it too often. I have a 420 sq-ft cartridge for a 20k pool so scaling by pool size, you could probably get away with a 225 sq-ft filter and have a similar cleaning cycle.

I can't decide on the intelliflo VS or VF. The VF is $400 more. I kind of like the idea that it will automatically ramp up in speed if the filter is dirty, or the solar panels are turned on, keeping the GPM steady. Not sure it justifies the $400 extra expense tho.

Keep in mind that if you are running solar most of the time and the panels are at a fairly high elevation (e.g. two story roof), then you will be using higher speeds most of the time and the economic benefit of having a VS are significantly diminished. This is one of the reasons that I converted my single speed 1 HP pump to a two speed 1/2 HP pump instead of going the VS route. Full speed is just enough to prime and run the panels at a decent flow rate and I still save quite a bit on energy costs when running on low speed when solar is not needed. But you said that you had no automation. Do you have a solar valve controller?

I have a Aquarite salt system too. Considering just selling it and going back to chlorine tabs. Sick of pouring acid in my pool all the time.

You could get an automatic acid feeder. I built my own shown here: Acid Injection System

But going back to tabs will likely result in too much CYA which can cause other problems. Also, lowering TA and adding borates can help with PH rise.

[wowser123]

Thanks everyone! It seems you ask three people which filter and you get the three different types. I really hate d.e. but might reconsider. Do you really need to run the filter longer to get the same filtration with sand? That would negate the expense of the intelliflo. I already have a 2 speed hayward 1 hp and blew a bearing after 1.5 years. Don't like the A.O. motors and the Northstar. Trying to get to the impeller on that thing is impossible. After rebates the intelliflo will be about $650.

[mas985]

You don't "have" to run a sand filter longer, only if you want it to remove the same debris as a DE filter. But even a longer run time may not match the filtering capability of a DE filter. Here is a fairly balanced comparison of each filter type: Filter Types

But to me filter run time is more about the circulation of the water than it is about filtering which is mostly for cosmetics. Keeping FC circulated during full sun and the heat of the day is far more important than removing every speck of dirt. On the other hand, it is very cheap to run the Intelliflo at low speeds so the extra run time would not be a big deal either. Solar is what will really negate some of the costs savings of the Intelliflo. But that is dependent on the details of your solar installation. If you do decide to go with a sand filter, just make sure you oversize it some to reduce backwashing frequency.

Also, is the the Intelliflo you are looking at have a built in timer? Most of the rebates require a controller, built in or external.