What is TDS?

[jhutto]

Link to FAQ on RODI/TDS and all you need to know on the subject from Reef Central:

 

[budsreef]

Chris, I hope you don't mind me asking a question in your thread. What RO/DI units are you guys using? I'm thinking about getting one and it would be one of the lower gpd units.

 

[george]

I'm using http://www.airwaterice.com/product/1TYPHOON">http://www.airwaterice.com/product/1TYPHOON</a>.

Price wise, it almost seems like the 50-100 gpd systems can be had for less than the 25-35 gpd systems.

 

[budsreef]

George;60150 wrote: I'm using http://www.airwaterice.com/product/1TYPHOON">http://www.airwaterice.com/product/1TYPHOON</a>.

Price wise, it almost seems like the 50-100 gpd systems can be had for less than the 25-35 gpd systems.[/QUOTE]

That makes sense according to the article referenced by jhutto! Higher output may not do as thourough of a job.

 

[george]

Budsreef;60169 wrote: That makes sense according to the article referenced by jhutto! Higher output may not do as thourough of a job.

True. Air, Water, & Ice doesn't recommend anything bigger than 75 gpd for their Typhoon systems.

However, I can't find any information that supports one TFC membrane in the 24-75 gpd range being better than another. All the Filmtec TFC membranes commonly used in both drinking and reef units are 98% except the 100 gpd. Kent's Hi-S membranes are 99%+, but come at nearly double the price which buys a great deal of DI resin to make up that difference.

Really the units marketed to the reef industry, like so many things that make the transition from "food grade" to that mystical "sold in a reef shop/online reef store" level, have simply been overpriced with marginal benefits at best. I don't think the lower cost of the high gpd systems is necessarily a result of less efficient so much as the companies that deal in higher bulk don't bother with the lower end because it doesn't pay in volume.

That doesn't mean there aren't crappy RO/DI units out there, of course.

 

[jetchris]

I am using a no name one from pets unlimited. The guy at the store told me they are used in the medical field but now they are targeting the marine world also. It is 25gpd unit. It has a total of 3 chambers. and a membrane.