DE vs Cartridge Filters

[jmce1587]

Since I will be new to the pool ownership stuff, I was wondering what the pros/cons are on a DE system versus a Cartridge system. Is one better than the other for water quality, ease of maintenance, cost of ownerhsip?

thanks

jmce1587

[CarlD]

Just go up and swat a big wasps' nest with a bat! It's safer than asking this question!

People with DE filters prefer DE. People with carts prefer carts, and people with sand (like me) prefer sand.

All three work, and work well, if sized and maintained correctly. All 3 have their advantages, and disadvantages.

You have to decide which you like and don't like. DE folks will tell you DE filters filter best. Cart owners like the convenience of not cleaning them often. Sand owners like the simplicity and reliability, as well as the ease of cleaning.

Personally, I've had a small cart for an Intex donut and hated it. Cleaning even that little one was tough and messy. Luckily they were cheap enough to replace once a month. Some carts use a single cart--much easier to clean. Others use multi-stage. Carts cannot be backwashed and don't usually have valving for water control like sand and DE. There are some tricks for maintain carts to make it easier, but I'm not expert on them. You cannot add DE to a cart to make it filter better, but there's a DE fiber substitute you can use.

DE can be simple or a pain. Many DE filters have a handle to "bump" when the pressure rises to resettle everything. Others don't and the DE community is split on their value. I have no idea, myself. When you backwash, you need to refill the system with more. At the end of the season the filter needs to be broken down and the screens or fingers inside cleaned and any tears in them repaired. I'm not sure of the soaking process, but you need to get off the organics first, I guess with bleach or electric dishwasher detergent, then you soak them in muriatic acid to get deposits off. DE has the finest filter quality, but that can be achieved with other filters as well.

Sand is the worst filtering medium because the smaller particles aren't trapped. However, as sand gets older and dirtier, its performance gets better and it gets smaller and smaller stuff. The sand lasts indefinitely, but even when you have to change it, it's cheap. Seasonal maintenance for me consists of draining it in the fall, removing the exterior valves and plumbing, and covering it for the winter. That's because unless you get out the sand, you can't move it (unlike carts and DE)--there's 200 pounds of sand, plus whatever water is trapped. You can improve sand's filtering by adding a little DE to it after each backwash. The seasonal cost of doing this is nominal as you are using FAR less DE than a DE filter. The boost in performance is amazing. You can also improve sand's performance by using a 2 speed pump on LOW--this allows the sand more time for filtering.

On ALL systems, you can improve performance with items like Skimmer Socks, or similar items--a stretch filter you put in the skimmer, "Slime Bags" that act like a second filter, and robotic cleaners. Most of them really polish your water as they run because they will cycle the whole pool's water and their filter bags are very fine--between a Cart's 20 microns and DE's 2 microns depending on brand.

I hope this helps. Remember: I'm biased--I own and prefer a sand filter.

[mas985]

One thing I would add to Carl's list is that if you decide to go with a cartridge, I would oversize it so that you do not have to clean it that often. The unit I have has 4 cartridges and I only need to clean it once or twice a year which takes about an hour to do. In fact, I end up cleaning the filter before I see any pressure rise.

One thing that forced me to a cartridge was the requirement of our city to use separation tanks with DE or sand filters. I guess this is to both save water as well as prevent pool water going into San Francisco Bay. Anyway, I might have gone with a DE filter had this requirement not existed. But after dealing with a cartridge for a year, I am not sorry I have it.