I have a five stage RODI and my tds going in my DI is only 4-6 and yet i only get about 60 gallons out of my cartridge before color is completely changed and tds is 1-2. What is the likely cause of the DI consumption?
DI consumption
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Are you on city or well water?
Are you on city or well water?
TaylorPilot
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CO2 levels? That will burn through resin, but doesn't show up on a TDS meter.
TaylorPilot
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https://spectrapure.com/TEST-KITS-METERS/CHEMICAL-TEST-KITS/Carbon-Dioxide-Test-Kit
Correcting is much more of a process. Basically, you have to take the water, put it in a container, aerate it so that it can off gas, then pump it back into the ro unit so that it can be processed. I don't know of anyway getting rid of it without opening the water up to the air so it can off-gas. In the video, they do it after the RO, but I would probably do it before. Reason being that water is a great way to filter air (rainbow vacuum cleaner). If you pump air through your clean water, any contaminates in the air will be filtered out into your clean water, raising the TDS. The issue with doing it that way is that you would probably need two pumps. A low pressure pump to feed the high pressure booster pump.
Correcting is much more of a process. Basically, you have to take the water, put it in a container, aerate it so that it can off gas, then pump it back into the ro unit so that it can be processed. I don't know of anyway getting rid of it without opening the water up to the air so it can off-gas. In the video, they do it after the RO, but I would probably do it before. Reason being that water is a great way to filter air (rainbow vacuum cleaner). If you pump air through your clean water, any contaminates in the air will be filtered out into your clean water, raising the TDS. The issue with doing it that way is that you would probably need two pumps. A low pressure pump to feed the high pressure booster pump.
let’s back up a lot. what rodi unit do you have? what membrane, filters and di cartridges do you have? what is your waste ratio? what is your rejection rate?
APEC Water Systems RO-90 Ultimate Series Top Tier Supreme Certified High Output 90 GPD Ultra Safe Reverse Osmosis Drinking Water Filter System (Dow) membrane. BRS color changing DI cartriges. Tds in greater than 350 in and 4-6 out pre DI and 0 post DI for a rejection rate of greater than 98%. Dont know the waste ratio.
TaylorPilot
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If that is the issue (not saying it is), that is the conclusion allot of people come to.
it won’t improve the rejection rate, as that’s not necessarily the problem. but it will help in different areas:
using high quality sediment and carbon filters will trap larger particles which extend life of the membrane and the di cartridges. the ones i linked at absolute/near absolute .5 micron. no other company rates this precise.
the di cartridges are crucial in any rodi system, especially if you have high co2 and you don’t want to create a degassing system. i honestly don’t know a single person who has set one up. so if you know you might burn through di, you might as well use the highest quality on the market. spectrapure is the only company that hand sources and mixes their di in-house. they have also developed their own formula that produces the highest quality water for the longest period of time. i should know as i’ve been using their products for 14+ years and i tested their new di cartridges when they were first released. the upfront cost will pay off in the long run. and when it’s time to replace your membrane, go with the spectrapure 99% rejection membrane.
Unlikely they'll help your situation.
If you tell me the pH and alkalinity of your RO water I can calculate your CO2
Degassing CO2 is very low cost and easy.
Russ
TheEngineer
Formerly icecool2
Do you have a pH probe for your tank?
You can do a bubble test to get a feel for whether or not CO2 is an issue. Take 1c of tap water and measure the pH. Then take the cup outside and run an air stone in it for 30 minutes. Measure the pH again. If it went up by a decent bit you had excess CO2.
Degassing is quite cheap and simple. The whole thing cost me $20. It is just a bucket, an air pump and some fittings. Then I gravity feed the degassed RO through my DI stage.
You can do a bubble test to get a feel for whether or not CO2 is an issue. Take 1c of tap water and measure the pH. Then take the cup outside and run an air stone in it for 30 minutes. Measure the pH again. If it went up by a decent bit you had excess CO2.
Degassing is quite cheap and simple. The whole thing cost me $20. It is just a bucket, an air pump and some fittings. Then I gravity feed the degassed RO through my DI stage.
