GE Merlin

[sleonard]

I have not yet decided whether or not to use RO at all. I have been told that I can use aged tap water and I believe it but raising several grand worth of Discus in 800 - 1000 tds, 8.2 pH tap water still makes me nervous. But then so does complex chemical treatments so I have decided that IF I do start using RO I will mix it 50/50 with filtered tap. A 50/50 mix gives me near perfect GH (125.3 ppm) and KH (71.6 ppm) and no need for expensive RO Right/Discus Essential madness although the Ph rises to 8+ after blowing off the CO2. (Last night I mixed 1 cup of RO w/ 1 cup tap and put in an airstone. Ph went from ~7.5 to 8.2 in an hour. Was still 8.2 this morning when I took the airstone out, will check again tonight)

Into this land of confusion and indecision comes the GE Merlin system that I just noticed at AirWaterIce.com and wow, that's one helluva system. @ 80PSI and 77 F it can produce 1400 GPD. Best of all, it's only $400!

So, for the price of one or two 75 - 100 GPD units (depending on what and where you buy) I can get a system that will handle all my current RO needs and provide for more expansion than I could even dream of needing and I dream a lot about a big fishroom :)

I was about ready to write off using RO completely until I saw this system. It is cheap, will expand effortlessly to meet expanding needs (I am planning on buying 2-400 gallons of tanks a year), and I can also use it for drinking water, icemaker, and the greenhouse I promised my wife. (If I get a fishroom, she gets a greenhouse).

What I need to know are the flaws in this plan. Do I really need it? Is the Merlin all that it is made out to be? This system sounds too good to be true, is it?

[RandalB]

It needs more pre-filtration than GE provides. Call Walter, he'll give you the details.

RandalB

[Discusgeo2]

I added 2-5 micon sediment filters to the one I got and works great. I got tired of waiting for the 75gpd units to fill my storage tanks.

[pwsusi]

Discusgeo2,
Just curious if the merlin does as good of a job stripping the water. What's the TDS of the water coming out of the Merlin? Does it burn through membranes any faster than a traditional R/O?

Thanks,
Paul

[sleonard]

It needs more pre-filtration than GE provides. Call Walter, he'll give you the details.

RandalB

Yep, I caught his recomendation for extra prefiltration. Any drawbacks that you've found?


I added 2-5 micon sediment filters to the one I got and works great. I got tired of waiting for the 75gpd units to fill my storage tanks.

How efficient is it w/ wastewater? Have you worked out the cost per gallon? Are you just using it for your breeder tanks? I remember you saying that you used Phoenix tap water for growouts and adults. I was almost ready to give up on RO and do the same until I saw the Merlin. It looks like such a relatively cheap source of RO that I'm considering using a 50/50 mix w/ Tempe tap water.

BTW, I'm still looking forward to seeing your fishroom. Looks like I'll have some weekends free in April.

Scott

[Discusgeo2]

Scott I haven't bothered to figure out the cost of the water. With the water being cold right now it fills my 210 gal tank in about 3 hrs. I am only using it on the breeders. The rest of the Discus are growing out on Phoenix tap water. My TDS wat 10ppm when I checked it. I don't know about burning thru membranes. If you are going thru membranes of you small R.O system you have something wrong. My 75 gal membranes are 4 yrs old and the TDS is still near 20ppm. Maybe you are not changing your carbon filter out fast enough. Also when mine are not in use I disconnect the membrane, let the excess water drain out and put it in the refridgerator until I need it again.

[korbi_doc]

:D Scott, at 800-1000ppms, is your water going thru a water softener?? Mine does, & that's why my tapwater is over 900ppms...it's (the softener) easier on the membrane, but high ppms, so I am using the R/O cuz of that...that being said, you can split the water out before the softener, run it thru the carbon & sediment filters only (if your water is nasty like mine) & not have to use R/O, or use it just for breeders...just a thought...
As to the ph, don't think that's as important if it's kept constant, cuz many ppl here keep their fish in high ph water successfully.

DiscusGeo, is that 10ppm a typo, or am I just misunderstaning what you said?.... Hope you are not raising your fish in that, not enough minerals for bone growth, keep mine around 300+ppms for youngsters & even now adults...maylbe you meant breeders???? Just wondering, Dottie ;)

[sleonard]

No water softener but those numbers were from my memory of the latest (2004) water quality report I found on the web and came from the city of Tempe. The numbers were actually:

Gh - 260 ppm average w/ a range of 109 to 338
Kh - 160 ppm average w/ a range of 116 to 268 and
TDS - 720 ppm average w/ a range of 300 to 1085
Ph - 7.64 average w/ a range of 7.31 to 8.20

I have since measured my Gh and Kh and they came out to be ~230 and ~ 125 respectively. I don't have a TDS meter yet so I can't measure that. I measured Ph at 7.85. The reported and measured Gh and Kh are low enough to use without RO but the reported TDS seems pretty high to me. Ph is fine as long as I properly acclimate the fish I order from breeders.

The more I think about it the more filtered tap looks to be the way to go. I think I am going to just install a 10 micron sediment filter, a 5 micron carbon and either another 5 micron carbon or a 1 micron carbon and have that go to a storage container for pre-heating.

[sleonard]

Oh, and I think DiscusGeo2 was referring to the output of the Merlin when he mentioned the 10 ppm.

[BIGFOOT]

With the Ro unit I have now which is a three stage unit I can get 140 gallons in 24 hours. Of coarse that is with a booster pump that boost my pressure to 84 Lbs. and a membrane pressure of 80 lbs. With quarter inch in comeing line.


Now from their ad I know they are useing a .375 inch line. My queston now is With a bigger line is their more or less rejection water? Logical thinking tells me yes. What I would want to know is at what rejestion ratio are they getting that much water and at what tds is the final water? Mine is 3 tds with old filters and starts at 268 tds.