pH / R/O Guru's please respond

[CottonMouth]

Here is something I never though I would have to worry about, with over 20 years in the aquarium trade I though i had Ph figured out, GUESS NOT.

I run a R/O system that gives 50 gallons a day, it is a 2 stage system. I change the carbon filter just about every other month and the mircon filter when it starts looking really yellow but before it turns brown. The main diaphram get changed every 6 months reguardless if it needs it or not. The water out of the tap is around 8.2 pH and very high in cal cabs, so its buffering capacity is unreal. pH down isn't much of an option really. Once through the R/O and I have 6.0 pH with very little change once nutes are added, somewhere around 5.6-5.8. Well I just changed my micron filter yesterday and the diaphram is only 3-4 months old, so really not ready for a changing, the carbon filter is less than a month old and still looks just fine. The whole thing has been fine until this past week, which prompted me to change the micron filter. The pH out was going up and once it reached 6.6 I decided it was in need of a change. In the process I back flushed the diaphram until it ran clear (like normal), drained all the water out of all of the chambers replaced the micron filter and started it back up. The drain out (R/O out) was at about normal speed not like it had any problems but when I checked the pH it was just like it was straight out of the tap. I let it run for 1 hour and checked it again and nothing had changed.
I have done nothing that I haven't done before with no problems, even the symptoms I had I have seen before and a change of the micron filter fixed it.

So what do you pH / R/O gurus think?
What could have caused it to go that high after a flush?
Could the diaphram have ruptured with just a back flush?
Or what is your opinion?

CM

 

[ogatec]

i would worry less about the ph until you add fertilizer & just measure the ppm or ec of the water comming out of the filter. if it is lower than 15ppm then you are doing good. as long as the ph is btw 6-8 comming out of the filter, it should only take a few drops of ph down or up to get it ideal since the buffering abilility of the filtered water is so low.


it seems like you are changing out your filters allot, i would go with a bigger size filter & you probibly wouldnt have to go thru so many. what is the starting ppm& ph of your water b4 filtering?


edit- after rereading your post, i guess the 1st thing i would do is replace all the filters with new ones to see if that helps. theres not really much more you can do with an r/o really, but if your ppms are fine i wouldnt bother......

 

[guineapig]

So do you think there's something wrong with the machine or the filters?

I'm obsessed with pH so usually i can address these issues but this one has me stumped....does that machine come with a troubleshooting manual?

Keep us posted if there are any additional details about the problem....

kind regards from guineapig

 

[CottonMouth]

I dont typically measure ppm's but if I had to guess with my pH being as high as it is and knowing where the water originates I would say that the ppm's are through the roof for tap water.
I am thinking that it is the diaphram of the system, I am just not sure what would have caused it to rupture like that. Like I said I have been in the aquarium hobby for 20 years or more and never seen a R/O diaphram rupture to a point that it would not work some what. But there is always a first, right now I can't change out the diaphram of the system until I can get one ordered.

In case you haven't figured out why I go so through so many filters is because of the fish I do keep and breed I have to change thier water more often than normal fish. They require very prestine waters to breed them. But that is another topic and kind of a give away to who me might be, at least if there are any people from my area that happen to see the post. LOL

I am going by the hydro shop today to pick up some pH down and I am also going to take in a sample of my tap water and see if they will do a ppm / ec / pH check of it and tell me what should be done to use the tap water here. I figure some pH down will work since I water with a run to waste hempy style grow. But using my tap water I might not need as many nutes added in. Hey saving money,, lol.

CM

 

[oregon bob]

CM, not a guru but understood that measuring the pH of RO water was essentially useless. First, w/o the salts to buffer, there is no stability in the pH of raw RO. Second, it is supposed to bleed the reference solution out of the meter. I have anecdotal evidence of the first, nothing on the second.

What I have noticed is that at varying times of the year, the total ppms of the tap changes drastically... several hundred ppms. This equates to a 20pt swing at my RO, which effects the measured pH by .5 or so. I'm fig there is additional calcium carbonate with the 20ppm swing. This is measuring the RO pH which is apparently unreliable, but nonetheless just for you to reference.

Hope this offers a little piece of the puzzle. Best.

 

[ogatec]

$15 on ebay will solve the mystery!

 

[CottonMouth]

how would $15 on ebay solve the mystery, if the diaphram is what busted or ruptured the only way to find that out is to replace it and I will when I get the new one in. But that is more of what the mystery was in the first place. What cause the pH to go from a normal R/O water pH of around 6.0 back to tap water pH of around 8.0
If you are refering to buying a pH and or a ppm tester there isn't a need for either one, unless I decide to use straight tap water. I can test my pH with my own test kit and for the ppm's, all my flowering plants get the same mix of 1tbs of bloom nutes and 1 tsp of cal/mag every other day and on the days inbetween they get 2 tbs of bloom nutes and 1tsp of cal/mag. Oh and once a week get straight R/O water, I use a run to waste system so I don't need to check the ppm's or the pH every day.

CM

 

[Hydro-Soil]

how would $15 on ebay solve the mystery,

I believe they were referring to an EC/ppm meter?

If your ppm is 15 or less, the diaphram isn't ruptured.