Spectrapure RO/DI 90gpd vs 180gpd? Difference?

[grom]

So Im looking at buying on of these tonight:
http://www.marinedepot.com/SpectraP...r_Systems-SpectraPure-SP1711-FIRORDNH-vi.html

I cant find anyone talking about the differences between 90gpd and 180gpd.


Does one require a more powerful inlet flow?
Does one last longer before I have to change filters?
Do I have to replace more filters with the 180, so it will end up costing me more to get the 180?
Does one do a slightly better job at 'cleaning' the water?
ect ?

I really need only 90gpd (in reality much less). But the difference between the 90 and 180 is only $10.

If there is absolutely no difference other than output flow, Id just get the 180...but this doesnt seem likely...

Can someone please clarify the difference please!

 

[grom]

wow.anyone?

I wanted to order mine now, but i dont know which...

 

[crvz]

my first thought is... that's a lot of money for an RO/DI system. If you check out some of the sponsors, such as airwaterice or buckeyefieldsupply, you can get very similar performance for probably half that price (a quick look at this model is a good example).

 

[grom]

I dunno, I just assumed that this unit would last a long time and all i would replace is the filters. If it last so long, might as well have a really good one.

I also read that over time the spectrapure comes out cheaper to operate.

 

[sirreal63]

Ok...a 92-96% membrane is not comparable to the Spectrapure 98% membrane. That is not similar performance.

SpectraPure Membranes have 98% average rejection (minimum 96%) Notice that BFS doesn't mention the rejection rate on any membrane other than the 150gpd one, and it isn't listed as a FilmTec membrane? Why isn't the min and max rejection rate listed? Or did I miss it somewhere?

I have used the cheaper membrane and yes it will produce 0 tds water but will use more DI to achieve that. I was one of those hard headed people who used a cheaper membrane for many years. Once I switched to the SP membrane I would never go back. The AWI and BFS systems work and are cheaper upfront, but not long term. I go from 300 tds to 1 with just the SP membrane, before the DI.

I also bought my stuff straight from SP, I don't trust when MD says list price of $515.99 and SP lists it as $349.99???? Who's list price is MD going by?
http://www.spectrapure.com/St_MaxCap-RO-DI.htm

You won't go wrong with the BFS or AWI unit, they are good quality at a good price but you can do better. Your initial thoughts were sound, stick with them.

 

[Stanley-Reefer]

Very happy in the year I've had my uhe 90 unit. It's very sturdy and works like a champ for me. My incoming water isn't that bad at 72-75 tds though.

I ordered mine from them as well.

 

[Waterobert]

+1 on spectrapure 90 unit. Had it for few months and still no need to change DI media.

 

[grom]

just purchased the spectrapure maxcap 90
I got marinedepot to pricematch 289.99 (from aquabuys). Which i think is a great deal.
so that made my mind on not paying 60bucks more for the 180.

I like marinedepot service, so i usually just have them pricematch. They have always matched the price for me.

 

[PaxRoma]

I don't use Spectrapure machine, but I use their membrane. My input tds is ~250 , and post RO is 1-2ppm. At first I thought may be the tds meter is off, so I verified with another meter and its the same result.

 

[celano]

I have used the cheaper membrane and yes it will produce 0 tds water but will use more DI to achieve that. I was one of those hard headed people who used a cheaper membrane for many years. Once I switched to the SP membrane I would never go back. The AWI and BFS systems work and are cheaper upfront, but not long term. I go from 300 tds to 1 with just the SP membrane, before the DI.

There are way to many variables in a ro/di unit for you to make such a broad statement like this. Initial tds readings from the tap, incoming water pressure, the micron ratings on the prefilters, and even water temp play a huge role in the membrane rejection rate which has a direct effect on how much di resin you use.
To say that the spectra pure is cheaper to operate over the long term may be true but just how long term are you talking? Two years? Five?...Ten? When does the cost of operation out way the initial cost of the unit? Especially when most people who get into this hobby don't last very long.

 

[prickles]

My understanding of RO systems is that they are cheap plastic things that direct water. The membranes/media are the only real difference. Some are probably better, but I doubt there's much difference that makes a difference in the plastic bits.

 

[Plato]

Ha-ha, been in the industry for 24 years. There are only so many manufactures of ro membranes and filter housings. The best performing membranes are Dow felmtech up to 75gpd, not their 100gpd. Up to 75gpd at 60 psi and 77F they are rated 98% rejection the 100 is only 92%. The 75 gpd at 80 psi will produce 90 gpd, mine does. I use spectra pure units because it is their tinkering with all of this stuff to come up with the maxi cap ro/di, before that was the 2000 system dual di. You can get 100 gpd membranes made with dow's felmtech role material, that is what I have now switched to. I get 120 gpd on average, 75 in 0 out. I buy spectra pures maxi cap di resin in bulk. If I knew which manufacture of resine beads I would just buy a bulk bag ( in the process of that). No, don't get the 180 gpd unless you have a booster pump even if your pressure is 60 to 70. My 180 gpd unit I changed the sediment and carbon canister to 1/2 threaded in/out to 3/8 jaco turbing 1/4 restricted the pressure on a single membrane 90gpd from 60 to 40 dual. After the upgrade I'm getting 60 on both membrains but still use a booster pump to drive at 100 psi on a 2/1 ratio. I basically have there UHF http://www.spectrapure.com/low_waste_systems.htm.
Want to know why it's a maxi cap 90 and not a 75. http://www.appliedmembranes.com/FilmTec Specs/TW30-1812-ALL.pdf
The 75 gpd will produce 20% more at ideal pressure and temp = 90 gpd. They use dows membranes.

 

[jeff@zina.com]

I cant find anyone talking about the differences between 90gpd and 180gpd.

The 90 GPD has a single membrane, the 180 GPD has two. It can process twice as much water in the same time. That's the only difference.

Jeff

 

[davehenri]

I purchased the 90 direct from Spectrapure and am very happy with it. It only runs when you do water changes and you take water from the storage tubs.