Checked my tds meter on my buckeye hydro rod unit and it read 0.001 TDS. Is this ok or should i change my prefilters, and di resin. System has been running since august 28 2014 made around 1000 gallons give or take.
rodi unit readding 0.001 tds
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OP
OP
alright thanks for the help. Its coming out of the di so i just ordered a filter kit. Right now i have my tds meter hooked up to my tap and di chamber. I really don't care what my tap water reads, how would i hook it up so i can read my ro tds reading, and di chamber? I think there more important than knowing how dirty my tap is which is in the 80 tds range.
It is not 0.001 TDS, they read in whole numbers not decimals so it is 1 TDS. What appears to be a decimal point is actually a power on indicator.
At a minimum it is time to consider a DI replacement but to know the condition of the RO membrane you need 3 TDS readings, tap water, RO only beofore the DI and the final RO/DI TDS. The first two are used to calculate the RO rejection rate or the efficiency of the membrane which does 90-98% of the work and the last is the DI condition.
Move the IN probe to between the RO membrane and the DI filter, the tap won't change much so its not real important to monitor that except when you want to calculate the rejection rate. I would highly recommend buying a good handheld TDS meter since they are more accurate and give you the ability to test wherever, not just two dedicated points and they are temperature compensated so much more accurate on the low end where it counts. I hve two dual inlines and never even use them since they never agree with any of my handhelds.
You would normally change your sediment and carbon block filters at 6 month intervals but with your low tap TDS, if you don't have sediment or particulate problems you might stretch it out to 9-12 months by watching your pressure drop. Don't forget to disinfect the system at least annually too.
At a minimum it is time to consider a DI replacement but to know the condition of the RO membrane you need 3 TDS readings, tap water, RO only beofore the DI and the final RO/DI TDS. The first two are used to calculate the RO rejection rate or the efficiency of the membrane which does 90-98% of the work and the last is the DI condition.
Move the IN probe to between the RO membrane and the DI filter, the tap won't change much so its not real important to monitor that except when you want to calculate the rejection rate. I would highly recommend buying a good handheld TDS meter since they are more accurate and give you the ability to test wherever, not just two dedicated points and they are temperature compensated so much more accurate on the low end where it counts. I hve two dual inlines and never even use them since they never agree with any of my handhelds.
You would normally change your sediment and carbon block filters at 6 month intervals but with your low tap TDS, if you don't have sediment or particulate problems you might stretch it out to 9-12 months by watching your pressure drop. Don't forget to disinfect the system at least annually too.
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OP
OP
Thank you. What is a good handheld tps meter? Also my unit is fairly new so I'm hoping my ro membrane is still up to par.
A good handheld is the HM Digital TDS-3, TDS-4TM or AP-1. A really really good handheld is the HM Digital COM-100 which does read down tenths of a ppm TDS and can also be used as a conductivity meter too. All of those mentioned are ATC temperature compensated and have a built in digital thermometer and read out so serve dual duty.
Keep up with the sediment and carbon replacements using high quality 0.5, 0.6 or no larger than 1 micron filters and if you have a water softener use softened water and the membrane should last 7-10 years or longer.
Keep up with the sediment and carbon replacements using high quality 0.5, 0.6 or no larger than 1 micron filters and if you have a water softener use softened water and the membrane should last 7-10 years or longer.
OP
OP
Alright thanks for the tips. I do come from a area rich in lime stone so the water is hard.will this affect the life of the RO membrane?
Yes, all membrane manufacturers recommend softened water. If you were dealing directly with the manufacturer and not a vendor such as Russ at Buckeye you would find the manufacturer will not honor a warranty claim if softened water was not used.
Soft water is the absolute best thing you can do for a RO membrane, raising the pressure like with a booster pump is the next best thing. A water softener does much of the work for the membrane by removing the calcium and magnesium and replacing them with sodium of potassium (solutes or salts) which are easier for the membrane to remove.
Soft water is the absolute best thing you can do for a RO membrane, raising the pressure like with a booster pump is the next best thing. A water softener does much of the work for the membrane by removing the calcium and magnesium and replacing them with sodium of potassium (solutes or salts) which are easier for the membrane to remove.
OP
OP
Well I forgot to mention I have city water so I think they soften it but not 100% sure on that. Another question I have is what is all the different kind of di resins used for. Example I saw some cation vs anion ones I know what these terms are just not how you know when to use the difference resins and not the usual mixed resin
Mixed bed DI which is what you commonly see in the hobby are a blend of cation and anion resins, one is negatively charged and the other is positively charged so between the two they attract about any contaminant left in the RO treated water. The blends are not a 50/50 mix in most cases and there are literally thousands of different resins on the market. You would not use only one or the other or it would mess with your water quality. Some people regenerate their DI using acid and Lye and keep them separated in different cannisters for ease of regeneration but still use both. I find this is not really a cost savings myself and don't like having the chemicals around the hosue for my grandkids to be messing with. I get enough chemicals at work.
I would stick with a trusted vendor such as Russ or Spectrapure is my favorite since they have done much research and development of resins over the last 25+ years. Their SilicaBuster and MaxCap resins are reef specific and the best you can buy. If you have a single DI the SilicaBuster or SuperSilicaBuster is the best bet and if you have dual DI I would use the Super MaxCap in the first canister and the Super SilicaBuster in the second. My softened tap water TDS is between 550 and 600, my RO only TDS before DI varies between 2 and 3 and I get over a year out of a regular MaxCap and 3 years out of a regular SilicaBuster. About a year ago I installed my first Super MaxCap and it is still going strong with 0 TDS out, I have not installed a Super SilicaBuster yet as my 3 year old regular version is still producing 0 TDS. That is with a 100G reef with 30G sump and a 16G nano here in Phoenix and cooled by fans and evaporation so I go through quite a bit of water in summer months via the ATO system.
I would stick with a trusted vendor such as Russ or Spectrapure is my favorite since they have done much research and development of resins over the last 25+ years. Their SilicaBuster and MaxCap resins are reef specific and the best you can buy. If you have a single DI the SilicaBuster or SuperSilicaBuster is the best bet and if you have dual DI I would use the Super MaxCap in the first canister and the Super SilicaBuster in the second. My softened tap water TDS is between 550 and 600, my RO only TDS before DI varies between 2 and 3 and I get over a year out of a regular MaxCap and 3 years out of a regular SilicaBuster. About a year ago I installed my first Super MaxCap and it is still going strong with 0 TDS out, I have not installed a Super SilicaBuster yet as my 3 year old regular version is still producing 0 TDS. That is with a 100G reef with 30G sump and a 16G nano here in Phoenix and cooled by fans and evaporation so I go through quite a bit of water in summer months via the ATO system.
OP
OP
Once again thank you for the all the information you just taught me. I already ordered from buckeye but I'm ganna go check out spectrapures. I found the hm digital com 100 for 50 bucks new. Is that a good price?
Good price, I paid $59 plus shipping 7 years ago for mine.
OP
OP
Alright cool going to have to put on my things to get list
If you found a COM100 for $50 new - $50 is below the allowable sales price issued by the manufacturer - make sure it is not a counterfeit. The market is loaded with them - they are a dime a dozen on Amazon and ebay. Its hard if you are not very familiar with the meters to tell a legit one from a counterfeit in some cases.
Russ
Russ
Remember that a reading of something above 1 ppm TDS on the DI really tells you nothing about the condition of your prefilters. From the FAQ's on our website: A good rule of thumb is to replace your sediment filter and carbon block after six months. A more precise way to maximize the usable life of these two filters is to use a pressure gauge to identify when pressure reaching the membrane starts to decline. This is your indication one or more of the prefilters (all the filters that touch the water before it reaches the RO membrane) is beginning to clog.Also be cognizant of the chlorine capacity of the carbon block. A good 0.5 micron carbon block for example will remove much of the chlorine from 20,000 gallons of tap water presented at 1 gpm. Some original equipment suppliers commonly provide carbon cartridges rated at 2,000 to 6,000 gallons. Remember that all the water you process, both waste water and purified water, goes through the carbon block.
Regarding your RO membrane and DI resin, use your total dissolved solids (TDS) meter to measure, record, and track the TDS (expressed in parts per million [ppm]) in three places: 1) tap water, 2) after the RO but before the DI, and 3) after the DI.
The TDS in your tap water will likely range from about 50 ppm to upwards of 1000 ppm. Common readings are 100 to 400 ppm. So for sake of discussion, let's say your tap water reads 400 ppm. That means that for every million parts of water, you have 400 parts of dissolved solids. How do we go about getting that TDS reading down to somewhere near zero?
If you do some experimenting with your TDS meter, you'll note that your sediment filter and carbon block do very little to remove dissolved solids. So with your tap water at 400 ppm, you can measure the water at the “in” port on your RO membrane housing and you'll see it is still approximately 400 ppm.
The RO membrane is really the workhorse of the system. It removes most of the TDS, some membranes to a greater extent than others. For instance, 100 gpd Filmtec membranes have a rejection rate of 96% (i.e., they reject 96% of the dissolved solids in the feed water). So the purified water coming from your 100 gpd membrane would be about 16 ppm (a 96% reduction). Filmtec 75 gpd (and below) membranes produce purified water (a.k.a. “permeate”) more slowly, but have a higher rejection rate (96 to 99%). The lifespan of an RO membrane is dependent upon how much water you run through it, and how “dirty” the water is. Membranes can function well for a year, two years, or more. To test the membrane, measure the TDS in the water coming into the membrane, and in the purified water (permeate) produced by the membrane. Compare that to the membrane’s advertised rejection rate, and to the same reading you recorded when the membrane was new. Membranes also commonly produce purified water more slowly as their function declines.
After the RO membrane, water will flow to your DI housing. DI resin in good condition will reduce the TDS in the RO water down to 0 or 1 ppm. When the DI output starts creeping up from 0 or 1 ppm, your resin needs to be replaced. Sometimes you'll hear people complain that their DI resin didn't last very long. Often the culprit is a malfunctioning RO membrane sending the DI resin high TDS water. This will exhaust the resin quicker than would otherwise have been the case. Sometimes the problem is poor quality resin – remember that all resins are not created equal.
Additionally, don’t forget to sanitize the entire system at least once per year, and wash and lube your housing o-rings with food-grade silicone grease every filter change.
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