Found out something interesting today and confused!!

[aereaus]

I never use the same container for mixing that I do for removing -- call me anal but my RODI has a TDS of around 2 if I upkeep it properly. Not sure if that's helpful. lol

 

[ryan paggi]

Is bottled water ok. I'm not thinking it is because of the minerals added right

 

[aereaus]

if it's purified it should be okay you don't want spring water, I probably would question their quality standards vs an RODI unit just made for fish tanks though.

 

[AZDesertRat]

If you buy bottled water make sure it is distilled water not bottled drinking water. The purple cap gallon jugs at WalMart are popular and most report good 0-1 TDS readings from it with a handheld meter.
Any decent RO/DI should produce 0 TDS water, the difference in a good system and a poor system is how long it maintains that 0 TDS. Often a low cost unit ends up costing 3 times what a good usint costs to own and operate since the replacements are much more frequent to maintain that 0 TDS. I paid more for my RO/DI unit but I can get over a year out of a DI cartridge with 550+ TDS tap water and a 100G display with 30G sump and a 16G nano in Phoenix AZ where evaporation is high. The system it replaced would exhaust DI in less than 150 gallons so actually cost me 5-6 times as much to own and operate in DI replacements alone. The current system is over 8 years old on the original RO membrane and still producing 99.4% rejection rate while the system it replaced required new membranes every 18 months and could never get even 98% rejection when new and got replaced at 95%. As you can see, there is a huge difference in filter, membrane and DI qualities and useful lives.

 

[aereaus]

@AZDesertRat I agree with that partially -- we have a Blue Marlin 1000 gpd RODI unit and it consistently reads between 1-2 even when everything is brand new. Something should be said for the quality of the source water. I'm sure if it were better our TDS readings would be lower.

 

[aereaus]

Either that or something isn't configured correctly haha could be an ID 10 T error

 

[AZDesertRat]

ANY RO/DI should produce 0 TDS, if it doesn't it has issues.
My tap varies between 560 and 900, it is hard as heck so I installed a water softener 8 years ago, we do have CO2 issues in the water and we have things like traces of rocket fuels, blue green algaes and other contaminants.
I produce around 150 GPD using a booster set at 95-100 psi and get 0 TDS out of the first DI for over a year and 0 TDS out of the second DI for over 3 years, these are normal 20 oz size DI cartridges. There is no partially about it, it should be 0 TDS period. If it doesn't you have areas that can be improved.

 

[aereaus]

I'll upload some photos of my setup later maybe you can help

 

[pondman]

I have noticed this as well with the buckets I use for mixing my saltwater.i just rinse them with ro/di water and then use.these buckets have only been used for my aquarium.i have one dedicated for waste water from my tank.

 

[jason2459]

Ok what kind of membrane would you suggest. Come to think of it I didn't replace that because I thought it was still good. I was thinking it was the pre filter that was the one that I needed to focus on

I would contact Spectrapure. They have, IMO, some of the best membranes and very good support to help get the best setup for your well water. If you don't have a booster pump you may need one but I would find out what your water pressure is.

Also, if the membrane starts to dry out it will not be good. I would replace it.

 

[aereaus]

The real shame in this hobby at least in my opinion is that a lot of guys with a wealth of knowledge and experience are also sanctimonious about sharing it. I have learned to overlook that aspect and just try to get good info where I can.

 

[jason2459]

The real shame in this hobby at least in my opinion is that a lot of guys with a wealth of knowledge and experience are also sanctimonious about sharing it. I have learned to overlook that aspect and just try to get good info where I can.

Yeah, wasn't worth commenting at all so edited the post.

 

[AZDesertRat]

I would also recommend Spectrapure but let's find out where the problem is before spending money on something that may not be the issue. It also helps you to learn about how your system works and what to look for in the future.

 

[aereaus]

Apparently our RODI unit was changed without my knowledge lol heres what we are running now along with some photos of our water room

 

[ryan paggi]

WOW to say the least. Well my tds meter isn't working right when I try to adjust it it goes down and then real high I guess that's what you get for a cheap one. So I will get a new one and will start there. Why do you need a booster pump if my system is running at 60 psi

 

[revhtree]

Great info in this thread!

 

[AZDesertRat]

At 60 psi you should be fine without a booster. I added one to improve the efficiency of my system even further and increase both the DI life and the gpd. The higher the pressure the more efficient the RO membrane becomes.

 

[scardall]

IMO it depends on what the TDS are more so than Quanity.

 

[AZDesertRat]

Which is a big reason to add a booster pump. You can pick up a couple percent TDS removal efficiency and for every 2% you can improve the efficiency you double the life of your DI resin. Doesn't take very many DI replacements to equal the cost of a more efficient RO membrane or a booster pump. They are improvements that pay you back.

 

[jason2459]

WOW to say the least. Well my tds meter isn't working right when I try to adjust it it goes down and then real high I guess that's what you get for a cheap one. So I will get a new one and will start there. Why do you need a booster pump if my system is running at 60 psi

60 psi is ok and I must have missed you saying that earlier if you mentioned it. I thought I would mention it as many on well water is much lower then 60psi and need a booster pump. Same with higher CO2 levels that can eat up DI quickly. Many membranes when you are seeing the rated GPD is based on certain qualifications. One of them is the water pressure. The lower the pressure the lower the GPD. The higher the higher the GPD. But this also has other effects.

Here's a good series of FAQ to read through

http://spectrapure.com/frequently-asked-questions


From SpectraPure
How do I calculate my membrane production?
How do I calculate my membrane output?
Membranes produce the rated gallons per day (GPD) at 60 psi (4.1 bars)
operating pressure, 77°F (25°C) operating temperature and 500 ppm total dissolved solids.
Membrane output gallons per day (GPD) depends on operating pressure, water temperature and the ppm TDS in the feed water.
Expected GPD = Rated GPD × PCF × TCF
PCF is the pressure correction factor
TCF is the temperature correction factor

Calculation of Pressure Correction Factor (PCF): The output (GPD) from
the membrane is directly proportional to the applied pressure.
Note: The membrane is rated to produce the rated GPD at 60 psi. For any pressure
other than 60 psi the output GPD is multipled by the PCF.
PCF = Line Pressure (in psi) ÷ 60

Calculation of Temperature Correction Factor (TCF): The output (GPD)
also decreases with decrease in temperature. This is because water viscosity
increases with decrease in water temperature.
Temperature Correction Factor Table (TCF)
°F /°C TCF °F \°C TCF °F \°C TCF
41.0 /5 0.521 59.0 /15 0.730 77.0 /25 1.000
42.8 /6 0.540 60.8 /16 0.754 78.8 /26 1.031
44.6 /7 0.560 62.6 /17 0.779 80.6 /27 1.063
46.4 /8 0.578 64.4 /18 0.804 82.4 /28 1.094
48.2 /9 0.598 66.2 /19 0.830 84.2 /29 1.127
50.0 /10 0.620 68.0 /20 0.857 86.0 /30 1.161
51.8 /11 0.640 69.8 /21 0.884 87.8 /31 1.196
53.6 /12 0.661 71.6 /22 0.912 89.6 /32 1.232
55.4 /13 0.684 73.4 /23 0.941 91.4 /33 1.267
57.2/14 0.707 75.2 /24 0.970 93.2 /34 1.304