Kinetico GX question

[Soaking]

Kinetico Plus-GX Membrane Assembly Replacement

I too have a Plus-GX system (1999 install) that we observed in 2010 the typical slow flow at faucet. We replaced the pre and post filters as normal thinking this was the issue, but continued to get slow flow. Kinetico service guy visited and said we needed new membrane (~$200.00). After reading the threads on the forum I'm now thinking maybe we have a storage tank (standard-white) or bladder issue. As I recall the service guy did not seem to remove anything from the system at the time.
Kinetico says the membrane alone is ~$200, but there is a sub-assembly component that is generally replaced at the same time that he says is ~$260 that they recommend be changed at the same time. In addition they say replacement of the membrane requires a special wrench, and that Kinetico does not sell the wrenches to the public, but rather they want their service techs to perform the task for ~$140. All total, ~$600.00 to get the system up again. I'm curious to know if the membrane is likely the cause of the slow flow. If so, does the replacement really require the special tool, or is it something a mechanically-inclined homeowner can perform successfully?
I've remoevd the GX manifold from the sink and taken the 2- new pre/post filters off. I removed the membrane cartridge from the manifold and see a 1/4" hex socket at the bottom. Could this be the sepcial wrench? Not sure how this cartridge/membrane assembly is put together. Is there a source for such info? Anyone have info on what's required for the replacement process?
Thanks.

[pawaterguy]

If you're getting flow then I doubt the subassembly is bad. When I've seen issues with them there has been no flow off the membrane due tot eh swelling issue of the subassembly. I'd check the tank and if the TDS is high coming off the membrane then replace it regardless. If I read that right you have an air charged tank? Drain it down and then check your pressure when it's empty. Also, lift it and see if it still has water in it after it stops giving water. If you hear sloshing around and it's heavy then the bladder is shot and the tank needs to be replaced.
The special wrench is a set of 2 actually. I carry them. One fits on top the membrane and on fits around it to separate them. The main cylinder unthreads from the "head" where the connections are made. Just watch the o-ring at the top. It slides around when you open it up and you need to get it back up into position before refitting things together.

[Soaking]

Thanks. Yes, it is the "standard", air-charged tank. The unit has been dormant for awhile so I'm sure the tank is empty/dry of any water. So I'll need to re-install the system and verify the pressure is ~7.5 psi and see how it performs and check the TDS. If the "membrane" itself is ultimately found to be bad, we'll replace it. What is the "sub-assembly" (~$260) that Kinetico suggested replacing with the RO-membrane? Is it the black cartridge outer-shell and head piece (female connections)? What's actually inside the outer-shell that attaches to the manifold other than a RO-membrane?
The special tool set sounds like it's tailored to the cartridge. With the special tool set I suppose the homeowner can replace the RO-membrane alone. Is it likely that early on Kinetico sold the tool sets also, but later discontinued? Any 3rd party access?

[pawaterguy]

Not sure about third party cuz I've never had to look for them. I was supplied them through my company. I wouldn't spend much money on them due to the few times you'll ever need them. Granted, they are a specialized thing that makes them priceless when you actually DO need them...but unless you can get them on e-bay or somewhere like that at a cheap price I wouldn't recommend owning them.

[Soaking]

Pawaterguy I'll send a PM.