I'm currently looking for an RO/DI system and have found a system I like. It's got some good features, 75 GPD Dow Filmtec membrane and a full size DI filter. The only thing I am unsure of is the prefilters. Reading around on here, it appears they are not up to scratch and will reduce the life of the membrane and resin.

I plan on changing the pre-filter for a 1 micron sediment filter, either a no brand product or a Pentek PS1-10C. The difference in price between the two is negligible.

As the carbon filter is not specified in the product description, I can only assume it is a low grade 5 micron affair. I want to replace it but am unsure of the best choice from the following. They are all pretty much the same price.

Pentek CBR2-10
Pentek ChlorPlus 10
Pentek FloPlus 10

Tunze offer a filter as well 8550.100 but I can't find any specs apart from a 0.5 micron rating.

Open to all opinions, thanks for the help.

Never mind, the water company sort of made the decision for me by dropping our water pressure. If I use the FloPlus I should still have enough pressure to avoid using a booster pump.

You can always reduce excessively high water pressure with a regulator.

As for prefilters, and assuming you have a 4 stage RODI, no chloramines in your tap water, and don't have unusually high sediment loads, go with 1 micron sediment filter and a 0.5 micron carbon block.

Russ

Many thanks, that's what I'm going with. I've found a good value system with two 10 inch prefilters and a 10 inch container for DI post membrane. I may add a 20µm sediment filter before the first prefilter.

I live in France and the systems on offer here from aquarium suppliers are either rubbish or super expensive. That's why I am having to "build" my own. If I do a good job of it, I may even try selling them to the aquarium stores/hobbyists here.

I am getting back into the hobby after a few years away and believe that the first step anyone planning a reef aquarium should take is to find a guaranteed source of quality water.