Canreef Aquatics Bulletin Board - Slow R/O unit water production

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- - Slow R/O unit water production (http://www.canreef.com/vbulletin/showthread.php?t=105555)

Slow R/O unit water production

What would cause an R/O unit to slow water production? I have a 100 gl/day RO unit (Vertex), and lately it is taking forever to produce 30 gls of water. By forever I mean I ran the unit from 4 pm yesterday afternoon and at 8:30 this morning I had maybe 15 gls of water. My membrane was changed a year ago and the filters 9 months ago. My TDS meter reads 0 so no reason to change anything. The unit is approx. 2 1/2 years old.

Previously, I'd run the water from 9 pm and by 7 am, I was close to overfilling the 30 gl container. I typically don't touch the unit and run it once a week, depending on outside temps. Length of time running depends on whether I've done a water change or not (fill one or two containers).

Do your pre-filters need changing?

I thought they might require a change as well, but the is TDS reading zero so I thought I could rule that out. Maybe not??

Is there anyway the restrictor was removed or maybe it's worn?

0 TDS is after the membrane. But when the pre-filters plug up and need changing, water flow will slow down to almost nothing. I now use a finer sediment (1st filter) and change it first, before the more expensive downstream carbon block filters get plugged. Otherwise they will plug as well, and you have to change the whole works.

Quote:

Originally Posted by Reef Pilot (Post 885341)

And this is why I love this forum so much!!! Thanks guys! I will try to pick up new filters in the next couple of days.

Hi I am also from Calgary. My R O production is down to. It is due to the cold temps we have been experiencing. Your water should improve now it is balmy outside. 😉

Quote:

Originally Posted by rogesue (Post 885349)

Hi I am also from Calgary. My R O production is down to. It is due to the cold temps we have been experiencing. Your water should improve now it is balmy outside. ��

Hmm, not sure that's the reason, I was running the unit yesterday and it was quite nice. I've never found temps to be an issue, only with evaporation. :biggrin:

Do you have a water pressure gauge? Handy item to help diagnose production issues & also when to change filters. I can often tell visually when my 1st stage 5 micron sediment filter is due for a change through the clear filter housing. It gets quite yellow/rusty looking. But the primary indicator for me comes through the use of 2 pressure gauges, one providing the source pressure (plumbed in before the first stage) & one providing pressure right before the RO membrane. This gives me a pressure differential reading & when that starts to rise, it's time to look at the pre-filters. The less pressure loss between pre filters (including carbon stage(s)) & the RO membrane, the cleaner they are.

Quote:

Originally Posted by Coralgurl (Post 885357)

Hmm, not sure that's the reason, I was running the unit yesterday and it was quite nice. I've never found temps to be an issue, only with evaporation. :biggrin:

Colder water will definitely have an impact on production. Membranes are designed to produce their rated output at a certain water pressure/temperature. I'll take a guess & those numbers are probably around 21 degrees C temperature & 60 psi water pressure. Any deviation from those numbers will cause a deviation from rated production. I stuck one of those strip thermometers on the housing of my 1st stage sediment filter and during the winter months the incoming water gets down to 8 degrees C. Highest incoming water temps I see are August through September when it gets up to a whopping 15 degrees C. That's still 6 degrees below the temperature at which my 75 gpd membrane would actually produce 75 gpd. Colder water means colder membrane which in turn means the tiny pores in the membrane will be smaller & more water will bypass instead of being pushed through the thin film. A day or two of mild weather will generally have little impact on the huge reservoirs most of our water suppliers use. My water comes out of Kalamalka lake, so it takes a long time for temperatures to change during the different seasons.

The positive side of colder water I've found is that I can get 0 TDS out of the membrane within 10 minutes of start up, saving on DI media. In the summer I never get 0 TDS from the membrane, best I can do is 1 TDS..... but production is faster....

Quote:

Originally Posted by mike31154 (Post 885366)

I'm going to check this out. I did notice the water in the container was ice cold as I refilled one of my jugs. I'm not sure what we tapped into as the water source - just told the hubby to get it done.....lol

I've only noticed production slowing down the last 2 weeks, not throughout the winter and we've had a helluva winter. Maybe its just a combination of cold water and dirty filters.

The only gauges are the one on the unit, I don't have any additional gauges to check on water pressure and in all honesty, don't recall ever looking at them...so dumb right...but I figure i'm getting the amount of water in the time I know it takes to fill so don't worry about it.