RO Water Filter Problems/Questions
Hey all,
Hopefully this is the correct forum to post this on.. I have a Water General RD-106 sold by filter direct. I changed out the 100gpd membrane for a 75 gpd membrane years ago. I did a water change on my fish tank the other day and noticed the following day that my booster pump also from filter direct (#752) was still running, So I looked at the pressure gauge located between the membrane drain line and the flow restrictor and noticed it was only at 40psi. I assumed my pre-filters were in need of replacement so I replaced them, turned the system back on, still only getting 40 PSI. So I disconnected the water line from before the pre-filters and connected it directly to the solenoid valve going into the booster pump to see if the problem was the Filters, When I turned it on, I'm still only getting 40 PSI. So I know the pre-filters are not the problem. I then tested the water pressure coming from the house/city to the RO unit and it tests at 62PSI. I assumed at this point that the RO membrane is may be bad/clogged.. so I checked the TDS after the pre-filters and got a reading of 386ppm and checked the water after the RO membrane before the DI resin and got a reading of 4ppm. So the RO Membrane is definitely working.. What else could the problem be? Why am I getting less pressure AFTER the booster pump than from the city? At this point other than blindly just swapping out the RO membrane hoping to fix the problem, I don't know what else to do? I am considering upgrading to a 2 membrane system using 2 150GPD membranes. If my current membrane is bad, this is the time to do it. I noticed filter direct sells a system with the 2 150 GPD membranes, but it uses 20" prefilters. Is 20" filters necessary to run the 2 150 GPD membranes? I don't use a ton of water. But when I need to do a water change in my tank, I need to make water as fast as possible. I might use 50 gallons a month including my Ice Maker and drinking water. My water changes are only 20g, but it takes 2 days to do a water change and I have to do 5 out, 5 in at a time due to having to wait many hours for the pressure tank to recharge. Thanks for your help. Any help is appreciated! Thanks, -ThaChad |
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The trick is using or should I say tuning the correct restrictor size. Originally I used the standard size and then finally added another behind it for less waste water. Your incoming is so high you have to use more caution then I did. |
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I do pre filter - carbon- carbon- booster- ro ro- di- one way check valve. If you have crud in the pump valves you will also get low pressure. Try running pre filter - booster and pressure gage and see if pressure goes to back to 90. |
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So I already knew what would happen, but I did as you suggested and hooked up the pressure gauge right into the out of the booster pump and it jumps all around between 90-130 psi.. But that's because there is no outlet, so it's just going straight to the gauge.. I don't have a T to check it inline.. Is there a way to clean/flush the "Pump Valves"? I did however check my TDS meter again and the TDS after the RO membrane is now at 11ppm.... So maybe the RO membrane is bad? Would flushing it help any? I don't have a flush valve so I'd have to do it manually. Thanks, -ThaChad |
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-ThaChad |
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The problem is the pump is not getting enough feed water, IF you are getting high pressure with just a pre filter and pump connected.
You do not need anything smaller then 5 micron for carbon or pre filters. They only remove large debris. They may be choking your pump out. I have the same rust issues you do. Only time my pump acted like that and I tore it down was when inlet pressure was down. |
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I nagated that problem when I bypassed the prefilters all together.. that is why i did that.. -ThaChad |
Can I add a 150GPD 2nd membrane to a say 75 GPD membrane for increased production? or does the membranes have to match in size?
Has anyone tried/used 3/8" housings? I see them available, but all the systems come with 1/4", I am guessing the 1/4" creates higher pressure, but at lower volume... I'm just curious if having all 3/8" lines, fittings, etc all the way threw would be beneficial? I realize it would take rebuilding my entire system, but Could be worth it IF it made a significant difference in production volume. Thanks, -ThaChad |
membranes have to match, generally 1 restrictor is used
stick with 1/4" water volume output, is dictated by membrane and restrictor get 2 100gpd membranes, even the cheap ones off ebay work great for me. |
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Mine has the solid White filter housings, so you can't see the filters. I wanted to get the clear housings, so that'll cost $45, the 150 GPD membranes are $55/ea, so that puts me at $155. Then I have to buy a 2nd membrane housing, that's another $15, putting me at $170, buy new filters, puts me at $195. That puts me about the price of a whole new unit... Do you know if satirizing the water with UV is good or bad or does it matter for reef? -ThaChad |
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I did this kit https://www.bulkreefsupply.com/brs-1...grade-kit.html best upgrade I have done Don't use the 150 rejection rates are different, I have had great luck with the cheapest ebay 100gpd membranes, but that's my own personal choice. stay with what you know, but 150 is wrong. |
home depot has clear 10" housings under 10 bucks. You only need 1 for pre filter and know to change our carbon when the prefilter gets dirty.
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100 GPD: https://filterdirect.com/product_inf...products_id=72 150 GPD: https://filterdirect.com/product_inf...roducts_id=205 75 GPD: https://filterdirect.com/product_inf...products_id=70 The rejection rate seems to be more dependent on prefilter condition and input pressure than by production rate, probably also the restrictor size. |
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You found that site, but many 75gpd have a 98% rejection rate, not found in larger sizes. The actual difference ends up being the amount of DI you will go through with larger membranes. |
Yeow guys... there a lot of not quite right info in this thread... ThaChad - feel free to give us a call if you'd like.
Russ |
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What specifically are you talking about that's "Not quite right"? Thanks, -ThaChad |
Happy to if people are interested - you are - so here goes... :)
In answer to the original question, it seems to me that you are using a 100 gpd flow restrictor with a 75 gpd membrane - not enough restriction - allows too much water to go down the drain. Quote:
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If you see a vendor where there are significant and common internal conflicts with the specs they report.... you might want to take that as a symptom of a larger situation. I'll let you connect the dots :) Quote:
Russ |
Thank you Russ for the info!
I got all my parts in to upgrade my system.. The pressure gauge that was/is on the waste line coming from the 1st membrane, that will now go to the IN on the 2nd membrane.. Should the pressure gauge remain in this location? or shoukd it be moved to the waste on the 2nd membrane? Do I need add an additional pressure gauge to read the pressure coming from both membranes? Also, do I need a 1/4 x 1/4 x 3/8 wye to connect the 2 product lines? or is a 1/4x1/4x1/4 wye going to have enough flow? Thanks! -ThaChad |
Why are you plumbing two membranes in series?
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Why not? -ThaChad |
You don't need two membranes to do that. Just change the flow restrictor on the first membrane for $4. But there are tradeoffs. Please call tomorrow during normal business hours if you'd like to discuss.
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I run mine before the 1rst membrane I have my pressure pump after pre filter and 2 carbon blocks. Gauge is there. Quote:
With low TDS your waste water is clean compared to most, so why not run it through another membrane. If your water is clean enough you can restrict flow even more to save that much more water. Buckeye is talking about tuning your system for optimum production which can be done with two membranes provided your water is not bad. I get away with 2 cheapys because my incoming water is only 27ppm tds, my DI last years in small cartridge housings. It would be silly to run just one membrane and not restrict flow even more then normal. I always have 0 tds before DI. Really this all depends on your TDS, buckeye will shoot straight they always do. |
My DS1 TDS Meter shows 386 TDS after the 3 pre-filters.. My water softener went out and I just got a new one installed today. So I will recheck the numbers tomorrow.
I got an 800 flow restrictor running 2 membranes in series. Which gives me a ratio of ~2.68 to 1. If my calculations are correct? Though I know I wont actually get 300 GPD, so that ratio is actually a bit higher? I Should be 80 PSI after the booster pump. I am rebuilding my entire RO. My primary reason for dual membranes is to increase production, though the using less water is an attractive side effect. Also I am changing from a 2x10 "inline" DI filter, to a 2.75 x 9.75 "Cartridge" style DI filter, I don't know if that will make any difference in my DI filtration/volume, but If I'm not at 0 TDS, I will add a 2nd "Cartridge" style DI filter. There is also the possibility of going to A Dual DI system, 1 Cation and 1 Anion cartridge, but that may be over kill.. Thanks! -ThaChad |
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