Okay so i picked up a tds meter today at walmart an decided to test all my water sources. Tap water measured at 52 ppm, my filtered water from the fridge measured 40ppm and my 4 stage ro system measured 14ppm. Does this sound normal? It seems as though my tap water isnt as bad as some, but i am worried about my ro water. Isnt it supposed to be at 0 ppm? Is 14ppm water good enough quality for a nano reef tank?
Ro water quality question
- Thread starter shibbyplustax
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Zoanut
Active Member
1) Your tap is VERY good, the best ive seen is around 15...but usually its 50-150 from taps. Wells 300-600+ (im 550-650+ on a well here).
2) Yes that sounds very normal, except....
3) Either your DI resin or RO membrane is wore out (in all likelihood just DI). Id head over to one of the sponsors here that deals in RO, get in touch with them and they will be able to walk you through what you need to replace and how much that will cost.
2) Yes that sounds very normal, except....
3) Either your DI resin or RO membrane is wore out (in all likelihood just DI). Id head over to one of the sponsors here that deals in RO, get in touch with them and they will be able to walk you through what you need to replace and how much that will cost.
Eric B
Well-Known Member
With that number coming out of your tap it should be zero on exit of the membrane or somewhere in the single digits. My tap water is in the mid 40's and most of the time zero out of the membrane but sometimes shows 1 or 2 out of the membrane.
How much waste water are you producing compared to good water? This is where I would start looking for your problem as I don't think it would be the filters before the membrane.
How much waste water are you producing compared to good water? This is where I would start looking for your problem as I don't think it would be the filters before the membrane.
Zoanut
Active Member
Anything over zero TDS means something is either not running correctly or DI and/or membrane is wore out. Sounds like your DI if you replaced the membrane.
Do you know what your pressure is? I couldn't get good clean consistent water output from mine until i bought a booster pump (usually not nescessary if you have city tap water, but i thought id ask).
I realized i didnt answer one part of your question (about what TDS is OK for a reef tank).
There is no hard and fast rule. A store in Detroit has some of the best looking corals around and he uses straight tap water (35 tds). If my TDS creeps up to 5-6 i get hair algae, diatoms and cyano everywhere.
Do you know what your pressure is? I couldn't get good clean consistent water output from mine until i bought a booster pump (usually not nescessary if you have city tap water, but i thought id ask).
I realized i didnt answer one part of your question (about what TDS is OK for a reef tank).
There is no hard and fast rule. A store in Detroit has some of the best looking corals around and he uses straight tap water (35 tds). If my TDS creeps up to 5-6 i get hair algae, diatoms and cyano everywhere.
If your system is RO only and not RO/DI it shoule be 90-98% lower than the tap water TDS. If you have a Dow Filmtec 100 GPD RO membrane it will be more like the 90% reduction as they are not as efficient as the 25, 50 and 75 GPD varieties that are 96-98% rejection.
If you have RO/DI then you need to do some further testing as it takes 3 TDS readings to trouble shoot a RO/DI, tap water TDS, RO only TDS before the DI and final RO/DI TDS. The RO only should be 90-98% less than the tap water and the RO/DI TDS should be 0. RO by itself will never be truly zero as a membrane is not a 100% efficient device by itself without DI. It may show 0 on some meters but TDS meters are +/-2 to 3% of full scale accurate devices and some are not temperature compensated so may not be super accurate.
How old is your RO? How old are the present sediment and carbon filters and the RO membrane? Is it a drinking water system and does it have a pressure tank and faucet? What is your water pressure and your water temperature? Have you checked the waste ratio on your RO to ensure the membrane is being well flushed when in use? Do you have a water softener or natutrally soft water?
What are you using to test and how are you doing it. Try this, get a nice squeaky clean, clear glass drinking water glass and wash it by hand in very hot water so it has no dishwasher soap residue, water spots or antispotting agents in it. Next since you have RO only get yourself a gallon jug of distilled water.
Triple rinse the glass and the meter in distilled water then fill it and take a TDS reading on the distilled to see if your meter reads 0 or very close to it, it should since it is clean. Next, let your RO unit run at least 10 -15 minutes to waste then fill the glass enough with RO to immerse the TDS meter probe, insert the meter and let it sit until the readings stabilize. What is the RO TDS reading now? Finally, triple rinse the meter and glass again in distilled water and put them away with the meter capped and the glass inverted so it stays clean.
If you have RO/DI then you need to do some further testing as it takes 3 TDS readings to trouble shoot a RO/DI, tap water TDS, RO only TDS before the DI and final RO/DI TDS. The RO only should be 90-98% less than the tap water and the RO/DI TDS should be 0. RO by itself will never be truly zero as a membrane is not a 100% efficient device by itself without DI. It may show 0 on some meters but TDS meters are +/-2 to 3% of full scale accurate devices and some are not temperature compensated so may not be super accurate.
How old is your RO? How old are the present sediment and carbon filters and the RO membrane? Is it a drinking water system and does it have a pressure tank and faucet? What is your water pressure and your water temperature? Have you checked the waste ratio on your RO to ensure the membrane is being well flushed when in use? Do you have a water softener or natutrally soft water?
What are you using to test and how are you doing it. Try this, get a nice squeaky clean, clear glass drinking water glass and wash it by hand in very hot water so it has no dishwasher soap residue, water spots or antispotting agents in it. Next since you have RO only get yourself a gallon jug of distilled water.
Triple rinse the glass and the meter in distilled water then fill it and take a TDS reading on the distilled to see if your meter reads 0 or very close to it, it should since it is clean. Next, let your RO unit run at least 10 -15 minutes to waste then fill the glass enough with RO to immerse the TDS meter probe, insert the meter and let it sit until the readings stabilize. What is the RO TDS reading now? Finally, triple rinse the meter and glass again in distilled water and put them away with the meter capped and the glass inverted so it stays clean.
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shibbyplustax
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Yeah idk whats goin on. I took the waste hose and clean hose and put them each in a 5 gal bucket and the waste water filled up about 1/2 (2.5g)the 1st bucket while the clean water barely filled up enough to cover 1/4 of the bottom of the bucket! I would say clean/waste ratio is about 1/40. No wonder why it took forever to fill my storage tank. Def going to get a new system and stop trouble shooting this one. Can i get a good system for under $100? Any suggestions?
A good reef quality system starts at $130 here:
Refurbished 90-GPD RODI System
Don't let the refurbished title sway you, there is nothing used or damaged about these systems, they contain the best of everything.
I wouldn't go any lower than that as you start giving up important features like high quality low micron filters, a treated and batch tested high rejection rate RO membrane, custom blended DI resin in a full size 20 oz vertical refillable cartridge and canister, inline pressure gauge etc.
Before you buy a new one, first try installing a 1/4" ball valve on your current systems waste line and throttling the waste back to 4:1 for a few hours then see what the TDS is.
Refurbished 90-GPD RODI System
Don't let the refurbished title sway you, there is nothing used or damaged about these systems, they contain the best of everything.
I wouldn't go any lower than that as you start giving up important features like high quality low micron filters, a treated and batch tested high rejection rate RO membrane, custom blended DI resin in a full size 20 oz vertical refillable cartridge and canister, inline pressure gauge etc.
Before you buy a new one, first try installing a 1/4" ball valve on your current systems waste line and throttling the waste back to 4:1 for a few hours then see what the TDS is.
