RO confusion... 4 stage, 5 stage, pumped...?

[The-Engineer-That-Brews]

Decided to take the plunge and get an RO setup to tame my hard-as-nails St Albans water, but I'm a tad befuddled over options and (as usual) there is quite a price range.
As it happens, I've already got a DI resin vessel that I use for the water I rinse the car off with - so I'm not sure whether that means I can buy a 4 stage versus a 5 stage setup?

I'm guessing I don't need need many litres per day, because I'll just be filling up a 30ltr bucket and I don't care how long it takes...

First option that's catching my eye is this "Vyair RO-50M 4-Stage 50 Gallons Per Day (189 Litres) Reverse Osmosis Water Filter System With MB-115 DI Resin Stage for Marine Aquariums and Window Cleaning" for £90 ... any views on that?

Many thanks in advance for any advice

 

[The-Engineer-That-Brews]

Following link seems to have a moderately sane description of the function of the different stages... The Difference between 2, 3 & 4 Stage Filtration

 

[RGeats]

Personally I would suggest you only need 3 stage filtration. The water coming out of the RO membrane will be very low in dissolved salts so will be fine to build your water profile from. I wouldn't worry about the small amount left after RO to bother getting DI. just make sure you look after the carbon filter to ensure your water is chlorine free before the RO.

 

[RGeats]

Do you need a pump for these systems? Looking at the link you sent it looks like you need 3bar pressure on the inlet.

 

[The-Engineer-That-Brews]

Do you need a pump for these systems? Looking at the link you sent it looks like you need 3bar pressure on the inlet.

Thanks - well, my water pressure here is very high indeed, and the whole house runs behind a pressure reducing valve - so if I go in upstream of that I should probably be OK :-)

Heh - just checked, and I've got 4 bar even after the PRV

 

[RGeats]

It looks like 4bar is the max for the system

 

[The-Engineer-That-Brews]

It looks like 4bar is the max for the system

That's fine - I can just connect it here, I think... do these things need a waste water connection to the drain too, and if so do they produce a fast flow or just a trickle please?

Many thanks for your help M

 

[RGeats]

I've never used a system domestically but I have used industrial RO systems running at 30bar. There will be a reject stream with concentrated salts, the technical specification should give you a % reject flow. I'm not sure if you can adjust this on these systems, but as you say you have hard water, the lower the reject flow the shorter the life of your membrane before you'll need to replace it.

 

[The-Engineer-That-Brews]

30 bar... blimey!

 

[The-Engineer-That-Brews]

I've never used a system domestically but I have used industrial RO systems running at 30bar. There will be a reject stream with concentrated salts, the technical specification should give you a % reject flow. I'm not sure if you can adjust this on these systems, but as you say you have hard water, the lower the reject flow the shorter the life of your membrane before you'll need to replace it.

Yes it's hard alright... 363 g/ml total hardness (145 g/ml calcium) full report

 

[strange-steve]

Yes it's hard alright... 363 g/ml total hardness (145 g/ml calcium) full report

That's some diamond hard water you've got there, check your units

 

[The-Engineer-That-Brews]

That's some diamond hard water you've got there, check your units

This is true, Steve! that would be a tad on the hard side, wouldn't it D'Oh!! I meant mg/l, didn't I (#facepalm). Incidentally, if the total hardness is 363 and the calcium is 145, what is the other 218 mg/l then?

 

[RGeats]

This is true, Steve! that would be a tad on the hard side, wouldn't it D'Oh!! I meant mg/l, didn't I (#facepalm). Incidentally, if the total hardness is 363 and the calcium is 145, what is the other 218 mg/l then?

Magnesium, and carbonates

 

[strange-steve]

Magnesium, and carbonates

Sort of, although it's not quite so straightforward. Hardness is a measurement of calcium and magnesium but it's not a simple addition, there are multipliers for each:
Hardness as CaCO3 = calcium x 2.5 + magnesium x 4.1

 

[BeerCat]

That's fine - I can just connect it here, I think... do these things need a waste water connection to the drain too, and if so do they produce a fast flow or just a trickle please?

Many thanks for your help M

View attachment 30161

I have a tank on my system as we use it for drinking as well. The waste is plumbed into the ubend under the sink and only produces a trickle.

 

[RGeats]

Sort of, although it's not quite so straightforward. Hardness is a measurement of calcium and magnesium but it's not a simple addition, there are multipliers for each:
Hardness as CaCO3 = calcium x 2.5 + magnesium x 4.1

Agreed, was just keeping it simple.

 

[The-Engineer-That-Brews]

And I thought water was the simple bit.... (runs away and hides)

 

[RGeats]

And I thought water was the simple bit.... (runs away and hides)

It is easy if you just follow Steve's basic water treatment guide!

I'm sure there are loads of people with PHDs just on water chemistry, so what chance have the rest of us got!

 

[AdeDunn]

Make sure to pick a system that can be run intermittently, or buy the parts/a kit to add this functionality yourself (it's pretty simple to do). Otherwise the waste will just run 24/7, even if you aren't using the RO.

I also went with a system with a tank. Was a 5 stage but I removed 1 stage as it was just a "flavour improvement" stage of another carbon filter that was supposed to go between the tank and a faucet, and never did use the supplied faucet... I also upgraded the membrane and flow restrictor on mine (was using mine for aquariums as well as brewing and wanted to produce filtered water faster). Usually extra stages are things like deionising resin to produce water for use in reef aquaria, where you want to remove silicates (causes diatoms to grow, making your lovely sand turn brown...), way too pure for brewing with. Stages in mine are the pre-filter (you may go off tap water after you see what happens to these after just a few weeks....), 2 types of carbon filter (block and matrix), RO membrane.

I don't use my RO for brewing any more though, as the more you strip out, the more you have to put back in again. So trying to wrap my head around using AMS/CRS to reduce alkalinity instead, which means I don't have to add as much. I don't brew lagers at all.

Nobody has mentioned, but if you aren't getting 1 with a tank, be prepared to prepare your water well in advance, they're not exactly fast (domestic ones aren't anyway). I used to prepare my water the night before brew day, and that's with a 6 litre tank.....

 

[The-Engineer-That-Brews]

Make sure to pick a system that can be run intermittently, or buy the parts/a kit to add this functionality yourself (it's pretty simple to do). Otherwise the waste will just run 24/7, even if you aren't using the RO.

I also went with a system with a tank. Was a 5 stage but I removed 1 stage as it was just a "flavour improvement" stage of another carbon filter that was supposed to go between the tank and a faucet, and never did use the supplied faucet... I also upgraded the membrane and flow restrictor on mine (was using mine for aquariums as well as brewing and wanted to produce filtered water faster). Usually extra stages are things like deionising resin to produce water for use in reef aquaria, where you want to remove silicates (causes diatoms to grow, making your lovely sand turn brown...), way too pure for brewing with. Stages in mine are the pre-filter (you may go off tap water after you see what happens to these after just a few weeks....), 2 types of carbon filter (block and matrix), RO membrane.

I don't use my RO for brewing any more though, as the more you strip out, the more you have to put back in again. So trying to wrap my head around using AMS/CRS to reduce alkalinity instead, which means I don't have to add as much. I don't brew lagers at all.

Nobody has mentioned, but if you aren't getting 1 with a tank, be prepared to prepare your water well in advance, they're not exactly fast (domestic ones aren't anyway). I used to prepare my water the night before brew day, and that's with a 6 litre tank.....

Thanks for the good advice. Interestingly on the subject of need to 'put stuff back' into RO water, my last brew was with 25 litres of water I collected from the UV treated springs on the Malvern hills. This is (I am reliably informed) pretty much devoid of all minerals. I pretty blindly added 12g calcium sulphate, 3g table salt and 2g magnesium sulphate; then I used it to brew a pale ale which was absolutely terrific. No problems with the mash utilisation, and the fermentation (with Safale S04) went like a train! If I can reproduce that reliably without having to drive all the way across to Malvern then I'll be a happy bunny :-)