Spectapure 180GPD question

Ert · Mar 10, 2018

Hi,

I'm running a Spectapure 180 GPD RODI 4 stage which uses two 90GPD membranes. Is it possible to instead use two 75GPD membranes?

Would they fit? Just curious. I would understand that the 180GPD would drop to 150GPD.
Please chime in

Crabs McJones · Mar 10, 2018

Ert said:
Hi,

I'm running a Spectapure 180 GPD RODI 4 stage which uses two 90GPD membranes. Is it possible to instead use two 75GPD membranes?

Would they fit? Just curious. I would understand that the 180GPD would drop to 150GPD.
Please chime in

I know the 50 and the 75 gallon per day units fit in the same housing, but I'm unsure of the 90 gallon per day unit. Let's see if someone from #reefsquad or if @Ryanbrs or @randyBRS knows the answer

Ert · Mar 11, 2018

crabs_mcjones said:
I know the 50 and the 75 gallon per day units fit in the same housing, but I'm unsure of the 90 gallon per day unit. Let's see if someone from #reefsquad or if @Ryanbrs or @randyBRS knows the answer

Great Idea. I'm actually interesting the Dow 75GPD membrane.
Pls BRS, chime in

Diesel · Mar 11, 2018

@Buckeye Hydro had this answer on his website.

http://www.buckeyehydro.com/faq/

WWIII · Mar 11, 2018

You should be able to no problem as long as you switch out the flow restrictor.

mjlash22 · Mar 11, 2018

Tagging along as I was actually considering upgrading my 75GPD membranes to 90, but was unsure if they would fit the same housing. I have a BRS unit though.

Ryanbrs · Mar 11, 2018

Ert said:
Hi,

I'm running a Spectapure 180 GPD RODI 4 stage which uses two 90GPD membranes. Is it possible to instead use two 75GPD membranes?

Would they fit? Just curious. I would understand that the 180GPD would drop to 150GPD.
Please chime in

The 90 and 75 are the same membrane.

Dow specs the 75 gpd membrane to produce 75 gpd day at 50 psi. However the same membrane at 60 psi it will produce 90 gallons a day. That said, most people will find their homes water supply to be closer to 50 psi.

We did a video on membranes and their flow rates at different pressures a while ago

Crabs McJones · Mar 11, 2018

Ryanbrs said:
The 90 and 75 are the same membrane.

Dow specs the 75 gpd membrane to produce 75 gpd day at 50 psi. However the same membrane at 60 psi it will produce 90 gallons a day. That said, most people will find their homes water supply to be closer to 50 psi.

We did a video on membranes and their flow rates at different pressures a while ago

By doing this is there an increase in output tds being that you're forcing the water through faster?

WWIII · Mar 11, 2018

I didn't know they were the same exact membrane. Interesting! So more pressure and a different flow restrictor?

Ryanbrs · Mar 11, 2018

crabs_mcjones said:
By doing this is there an increase in output tds being that you're forcing the water through faster?

Actually the membrane performs better with higher rejection at higher pressures

Ryanbrs · Mar 11, 2018

WWIII said:
I didn't know they were the same exact membrane. Interesting! So more pressure and a different flow restrictor?

Well you would have to ask them that question but I know in the past the forum community has shared that they have been told it is Dow material with their sticker. I doubt the flow resrictor would be significantly different because most people are actually close or even under an effective 50 psi and getting 75 gallons a day or less.

It’s posible that has changed but there are only a handful of RO membrane manufactures in the world. Dow is the leader/bar and I believe the only one that produces a 75gpd with 99% rejection. That membrane will do 90 gallons a day at 60 psi

You can check out the flow rates of the dow 75 GPD membrane at different pressures on the spec sheet. http://msdssearch.dow.com/Published...seps/pdfs/noreg/609-50165.pdf&fromPage=GetDoc