[rb4no]

hi guys so I have a 4040 system which has served me great over many years. Because my water pressure is so low what I do is have water pass through the pre filters into an IBC tank, then once full I then draw that water via a booster pump through my RO into another IBC Tank. I've noticed on the past two fill up that the output on the RO has diminished considerably. Any thoughts as to why this is the case? cheers

[Small but perfectley formed]

Could be Temp of water or your RO s are scaled / end of life

[rb4no]

would it just to from normal to like a third of flow overnight if scaling up or end of life? Would've thought it would be more gradual

[Perfect Windows]

Could also be bacterial contamination, which can go from zero to 100mph in a few days.

That would have the side effect of increasing your TDS, which you haven't mentioned.

Vin

[Spruce]

I have found the same with my 4040 recently.

My 4040 membrane is 12 years old and still producing at a rejection rate of 97%.

It was definitely taking much longer to refill my IBC storage tank, so I did some investigation.

When I first put the 4040 together, it was producing 2 litres of pure per minute. My waste water was just over 2 litres per minute. Last week I was producing 1 litre of pure per minute with approx 1.5 litres of waste per minute. My water pressure both sides of my prefilters is 50psi, which has been this for around 15 years.

The TDS of the incoming tap water was 148ppm, when it's usually around 124ppm. The incoming tap water temperature is 5.7 degrees C. I haven't seen it this cold before.

As my rejection rate is still good, I've decided to stick with my current HF5 membrane and see what happens in the summer when the tap water's temperature improves. I throttled the waste tap back a bit more to get a little less waste, but I haven't checked the new performance figures.

I suspect that the membrane has got clogged with calcium, but the production drop-off seemed to suddenly happen, so this has got me wondering if its just the incomming tap water temperature.

[Bungle]

This has reminded me that I have to do a flush. Can't remember the last time I did one 

[rb4no]

ok so i've binned the old filter and in the process of replacing it with another filter that I had bought new and had little use. Does anyone here have any experience with recommissioning an older filter, it should work like new .  Should it just work from the off or would there be a process to it. thanks lads. Richard

[dd]

Assuming you mean the RO membrane I don't think it does them any good to be left standing if you used it for a while then left it.

[Perfect Windows]

Assuming you mean the RO membrane I don't think it does them any good to be left standing if you used it for a while then left it.

Seems possible to me too. They used to come drenched in preservative so if it's old enough, you'll have washed that out. They now come bone dry but you've put water in and presumably left it damp.

Either way, you're at risk of biological fouling but the only way to know is to give it a pop, I guess.

As for commissioning it, with the newer ones (the dry ones, which yours might be now) the advice (from Gaps Water, no less) is to fit it and fill the housing then leave it to soak for a few hours but not under pressure.

Vin

[JandS]

If I'm not using system for a few days for holidays etc I flush it through with pure till waste reads near enough 0....that way it's not stood in high TDS water.

[rb4no]

thanks guys, been mucking about with it for two solid days, and bought a new membrane which will arrive early next week. Interestingly i've also been doing some litres per minute measurements and found a couple of areas where I could improve flow. One is the float valve, that max's out at 7.5 lpm, i've now changed it to a high flow one so it flows like the tap does, but surprisingly my water softner (IONICS unit) really drags down the flow. Any thoughts on keeping the softner, does it really help the RO? I live in Norfolk so very high TDS here.

[dd]

If you want to use a water softener why not just use a standard one, the same type you might use in your house.

[Spruce]

thanks guys, been mucking about with it for two solid days, and bought a new membrane which will arrive early next week. Interestingly i've also been doing some litres per minute measurements and found a couple of areas where I could improve flow. One is the float valve, that max's out at 7.5 lpm, i've now changed it to a high flow one so it flows like the tap does, but surprisingly my water softner (IONICS unit) really drags down the flow. Any thoughts on keeping the softner, does it really help the RO? I live in Norfolk so very high TDS here.

A water softener doesn't actually soft the tap water. What it does is removes the calcium and magnesium ions in the water and replaced those ions with sodium ions
 Sodium ions are much kinder to r/o  membranes.

A water softener takes time to exchange these ions. It's similar to using resin as that also needs time to work it's magic

[Scottish Cleaning Service]

One thing I realised is:- membranes don't like the frosty weather. If they become frozen then it can set the shape inside meaning it takes longer to produce.

[Bungle]

One thing I realised is:- membranes don't like the frosty weather. If they become frozen then it can set the shape inside meaning it takes longer to produce.

I wrap mine with old blankets over the winter.

[Scottish Cleaning Service]

One thing I realised is:- membranes don't like the frosty weather. If they become frozen then it can set the shape inside meaning it takes longer to produce.

I wrap mine with old blankets over the winter

I turn my oil filled rad on when minus weather during the night.

[Bungle]

One thing I realised is:- membranes don't like the frosty weather. If they become frozen then it can set the shape inside meaning it takes longer to produce.

I wrap mine with old blankets over the winter

I turn my oil filled rad on when minus weather during the night.

My RO is in the garage. Oil filled rad wouldn't do owt in there. Blankets are on filter housings, RO, hoses and DI. Roll on a couple of months.