Which is more important? RO or DI?

[CalmSeasQuest]

Ok I'm beyond frustration here! I need to treat my water with something. If not this then what? Suggestions? And please don't say an RO/DI unit.

First.....relax

Best option - not allowed to say

Alternatives - Friend or neighbor with a RO, local store that sells RO (i.e. supermarket) look in the phone book, often water treatment companies sell RO water.

The best long term option is the unmentionable.

Have you tested your water? - TDS? Although not a best practice, there are many that have thriving reef systems using tap or well water. I was amazed to learn the Tropicorium supports their entire operation using many thousands of untreated Detroit city water weekly. If you're not having nutrient/silica/phosphate problems (i.e. algea, cyano, diatoms...) then just keep doing what you're doing and save your nickels for an unmentionable

[MizTanks]

First.....relax

Best option - not allowed to say

Alternatives - Friend or neighbor with a RO, local store that sells RO (i.e. supermarket) look in the phone book, often water treatment companies sell RO water.

The best long term option is the unmentionable.

Have you tested your water? - TDS? Although not a best practice, there are many that have thriving reef systems using tap or well water. I was amazed to learn the Tropicorium supports their entire operation using many thousands of untreated Detroit city water weekly. If you're not having nutrient/silica/phosphate problems (i.e. algea, cyano, diatoms...) then just keep doing what you're doing and save your nickels for an RO/DI.

You said it!!! then just keep doing what you're doing and save your nickels for an RO/DI. Lol

[CalmSeasQuest]

You said it!!! then just keep doing what you're doing and save your nickels for an RO/DI. Lol

Nope - look again

[binford4000]

There is no such thing as getting too much in a RO/DI. You either get one thats reef quality or one that is not.
When you get a reef quality system you get 0 TDS not 0-20 TDS. The advantage of buying a better system is lower overall cost of ownership due to reduced maintenance requirements and filter/DI changes. Yes you may pay a little more upfront but it is returned many times over the life of the system.

80 TDS out of the tap is very good but still not reef quality and it would require a RO/DI to get that to 0 TDS. You could do it with DI alone but the cost of resin replacements or recharging would soon exceed the cost of the reef quality RO/DI in the beginning.

20 tds is still reef quality water,really it's a 29 gal tank she has and it will take years for a filter and di change even on a cheap unit.Matching the unit to the systems needs is only practicle.If she has 80 tds out of the tap she can run it thru just about any filter system and get quality water.

[AZDesertRat]

Unfortunately most Marc Weiss products are snake oil and have a horrible reputation in the industry.

There is no substitute for (unmentionable), plain and simple.

If you cannot afford one then find a trusted source. Of course (unmentionable) is the best choice but you will probably only find it at a LFS as other hobbies don't use it much. Second choice is distilled water in the gallon jugs at the grocery, it should be very close to 0 TDS too. Third choice would be RO only from a manned or staffed Water & Ice type store which usually have knowledgable staff and will have a TDS or conductivity meter to show you what you are buying beforehand. I have had very positive results at the stores when you tell them what you are using it for, they seem very proud of their product and bend over backwards to please you, especially if you have a few photos of your reef! Its RO only but usually very high quality and only 25 cents a gallon .
Fourth choice would be gallon jugs of RO from the grocery as long as they do not say remineralized which means it has TDS added back in for taste.
Last choice would be a vending machine since they are not regulated by health agencies and you are at the mercy of the vendor who is treating it for taste not for a reef so quality can be all over the place.

[AZDesertRat]

20 TDS is nowhere near reef quality water, who told you that? Get real.
The problem with TDS is you have no idwa what the TDS consists of, it could be phosphates, silicates, nitrates, copper etc. You don't have a clue and hobbyist grade test kits do not work well on ultrapure water so don't suggest it.

Filters get changed every 6 months on a RO/DI no matter how much water you make. Extending the changes increases the likelyhood of bacteria, virus and algae growth inside the housings and filters since we are providing the perfect environment for them to multiply and grow with warm still water, clear housings and absence of a residual disinfectant since we removed it with carbon.

[jimsflies]

I guess the question I have for Jamie is, what problems are you having with your tank? If its algae/phosphates then you might be able to band aid the situation with some phosban in a filter sock tucked inside of your HOB.

If there isn't a problem and you want an RO/DI to just do better...then I wouldn't add any other chemicals of suspicious content to the water. If it's not broke don't fix it approach.

[binford4000]

20 TDS is nowhere near reef quality water, who told you that? Get real.
The problem with TDS is you have no idwa what the TDS consists of, it could be phosphates, silicates, nitrates, copper etc. You don't have a clue and hobbyist grade test kits do not work well on ultrapure water so don't suggest it.

Filters get changed every 6 months on a RO/DI no matter how much water you make. Extending the changes increases the likelyhood of bacteria, virus and algae growth inside the housings and filters since we are providing the perfect environment for them to multiply and grow with warm still water, clear housings and absence of a residual disinfectant since we removed it with carbon.

WOW,I never change my filters tell my TDS is above 40,and even that's extreme in allot of peoples opinons/To change filters by calendar dates regardless of if it needs to be changed is a very extreme regiment for sure.The filter company's love you for sure.Me I'll pass and use real measurments to decied when to change em.Each their own.Gotta go with Jims reply "if ain't broke don't fix it!"

Anyome out there know what the TDS or real ocean water is?? 20 parts per millon is dirty?

[jimsflies]

I think its a good point that TDS can consist of anything...one person's TDS of 20 if it is all phosphate is a bigger deal than someone else who has a 40 TDS and it is all calcium. But in the interest of safe advice, we have to assume the worst case.

TDS is just a number...and we can say 0 TDS will always be good whereas higher levels are going to be hit or miss.

@binford...you are on DWSD (detroit) water. The Trop is also on DWSD water...so it is no surprise to me that you can get by with 40 TDS. The Trop for example uses straight tap.

[AZDesertRat]

OK, a little schooling is in order.
First off prefilters and carbons have very little to absolutely nothing to do with TDS. Think about it, they are in the 10, 5, 1 or maybe 0.5 micron ranges. Thats suspended solids.
TDS or dissolved solids are in the 0.0001 micron range, many many times smaller than those are capable of removing.
You CANNOT use TDS as a gauge or measure on when to change prefilters and carbons, theye serve two different purposes. TSS (sediment, particulates, colloidal materials, silt etc) is removed by the prefilter and carbon along with chlorine and some VOCs. They are there solely to protect the expensive RO membrane whose job it is to remove 90-98% of the TDS with the DI resin getting the rest.

What you need to understand with TDS is if any is present, its possible you have more than you know. Weakly ionized substances like nitrates, phosphates and silicates are just tha, they contain very weakly chaged ions so do not measure well on a TDS meter. You can have high silicates and phosphates in the treated water and not even know it. Another very very important point is DI resins starte releasing these weakly ionized substances even BEFORE it is exhausted. That means when you start seeing 1 or 2 TDS up for 0 TDS you are starting to release contaminants the DI resin has attracted over time and put it back in the treated RO/DI water. Since they are weakly ionized you may not see them and again they will not test well on a TDS meter or hobbyist grade test kits since it is ultrapure water, but rest assured they are present if they were in the tap water.

You always change prefilters and carbon blocks every 6 bmonths like clockwork. At this same time it is advised you disinfect the system with household bleach following the directions I have posted many times to reduce the chances of virus and bacteria growth. You change the RO membrane when it is no longer cost effective to keep changing DI resins frequently and you change the DI resin when it is anyting other than 0 TDS on a regular basis.