PH. and my /DI filter

[rgfast]

can anyone explain to me why I get a ph reading of 6.44 with /di filter and 7.98 if I bypass it. I've been chasing low ph for two months an this where it has lead me my test show alk. 9.5 dk cal 450 and mag 1350 but ph stays between 7.77 and 7.99 at end of light cycle. just made new bach of water without di filter an ph is 8.01, I have 600ft. well with really good water so don't freak on me

 

[BLAKEJOHN]

Are these readings of the freshwater from the output of the DI or are they after you mix the salt and let airerate for 24hrs.

If you're using a saltwater PH kit on freshwater I dont think it works well.

Also I wouldnt fret the PH much. As long as it is constant and all other params are normal and stable you shouldnt have any problems. I almost never check my PH unless I am raising my Alk and that is only to monitor the impact on PH.

 

[DaveK]

A pH of 6.44 right out of a RO/DI unit is about right. This is because RO/DI water has nothing in it. This makes it of very low ionic strength. This alone causes pH readings, especially when done with a meter to skew somewhat. In addition most meters used for SW systems are usually calibrated using buffers of 7.0 and 10.0, so being off a little bit here will also have an effect at the extreme ends of the calibrated area.

 

[rgfast]

the water I've been testing is the ro/di with out mix,I use Hanna ph montor cal. with pinpoint 7.0 I also check after mix and I mix my water after weekly water change 40gls per week 12%. My water change system is custom built arcylic 48"x24"x24" split one half is flow threw exc. the other half is mixxing tank it has ATO cir. pump and heater when needed due to the fact it nomally maintains same temp as tank water

 

[rgfast]

what I have learned, 1st that the ph of my fresh water doesn't change my salt water ph. I've mix new water at 6.44 threw ro/di and at 7.98 with the /di in bypass same end ph either way. I'm hard headed but will figure this out! Now I'm making new batch of water with diffent brand of salt and will let it cure for at least 24 hours before bashing my old brand.

 

[Rhodes19]

Ive been wondering about pH and fw vs sw. I have a Milwaukee meter and it reads my sw around 7.9-8.3 but my tap water at 9.6 and my ro/di water at 9.6 as well. I had city water come out and test the pH of the tap and they said it was 8.11. Must be the meter in my case. I'm thinking deferent meters must be used for fw and sw, given that different chemicals are used in aquarium test kits for fw and sw. Well, thats my feeble attempt at logic!! LOL

 

[rgfast]

I believe I might be on to something here, new batch the ph is higher so I'm going to say IO/RC salt is large part of my ph drop. I switched to this salt couple of months ago bacause I liked the pers. of it alk 9dk cal 440 and mag 1300 I still had bucket of Red Sea coral pro witch tested alk 7dk cal 480 and mag 1200 resson for changing was the low alk to sum this up order 4 buckets of Sea Chem aqua vitro will up date after new salt gets here

 

[Boomer]

can anyone explain to me why I get a ph reading of 6.44 with /di filter and 7.98 if I bypass it.


have a Milwaukee meter and it reads my sw around 7.9-8.3 but my tap water at 9.6 and my ro/di water at 9.6 as well.

You can NOT measure the pH of DI water or RO/DI water with a std pH meter. You need a special Ultra-Pure water pH probe, which is an arm and leg. There is nothing in the water for the pH meter/probe to ref at. You can measure the pH of RO water. That is why you see readings all over the place form different people on DI output water. The pH of RO/DI water, despite what the meter says, will be in the mid- pH 6's - 7.1 depending.

 

[Rhodes19]

can anyone explain to me why I get a ph reading of 6.44 with /di filter and 7.98 if I bypass it.


have a Milwaukee meter and it reads my sw around 7.9-8.3 but my tap water at 9.6 and my ro/di water at 9.6 as well.

You can NOT measure the pH of DI water or RO/DI water with a std pH meter. You need a special Ultra-Pure water pH probe, which is an arm and leg. There is nothing in the water for the pH meter/probe to ref at. You can measure the pH of RO water. That is why you see readings all over the place form different people on DI output water. The pH of RO/DI water, despite what the meter says, will be in the mid- pH 6's - 7.1 depending.

Hi Boomer,

Thanks, that makes sense for RO/DI but does that also apply to my tap water? I measured it at 9.6 but the city water folks measured it at 8.11. I must be missing something.

 

[Boomer]

No, not for the city water. When is the last time you calibrated that probe ? What do you mean the city folks measure it ? At your house they measured it ?

 

[Frankie]

No, not for the city water. When is the last time you calibrated that probe ? What do you mean the city folks measure it ? At your house they measured it ?

Hey Boomer, Happy belated B day buddy Good to see you. (trust me!)
No, Rhodes is in my town. He must be referring to the water news letter we have available.
By the time the water reaches us Chris, the PH drastically changes from it's travels from North Charleston to West Ashley. On top of that, the water plant is a natural bed, kinda like an algae scrubber but on a huge scale. The water is then treated and then piped to us. I bet your PH is different then mine coming out of the faucet. I'll see what mine is with my PH meter is you want to compare.

 

[Rhodes19]

No, not for the city water. When is the last time you calibrated that probe ? What do you mean the city folks measure it ? At your house they measured it ?

Hi Boomer, and happy belated birthday.

I calibrated my probe the same day I started testing the water when I realized I was getting odd number. The solution I used to calibrate my probe was 7 pH. I usually try to assume the problem is at my end first and work from there. The city folks were techs from the city water department. After communicating with the costumer service and telling them my readings, they sent a tech to the house and took a sample from the out side faucet. They measured the tap water at the house at 8.11 ph and left one of those paper door knob hangers with the info on it. I've seen the info sheet Frankie was talking about but I didn't know about the rest of the info. Interesting.

 

[Boomer]

9.6 vs 8.11

That is possible, depending on how long the water was in the line when the pH reading was taken and what the city has added to the water. One should let the water run to clear the lines first. It sound like they are adding sodium hydroxide to the water for anti-scaling. They do that here too and our pH is 9.1

 

[Rhodes19]

9.6 vs 8.11

That is possible, depending on how long the water was in the line when the pH reading was taken and what the city has added to the water. One should let the water run to clear the lines first. It sound like they are adding sodium hydroxide to the water for anti-scaling. They do that here too and our pH is 9.1

Thanks Boomer,

From what I read, the city adds lime to adjust the pH and adds orthophosphate to prevent corrosion of the water pipes. Well, as long as my probe is accurate for my sw tanks, that's my main concern.

 

[rgfast]

at my reef club meeting yesterday I was told that due to the low ph of ro/di water that I should buffer makeup water before adding salt to bring it up to 7.5 in order to get propper ph level of water change water

any thoughts on this

 

[BobBursek]

RGfast,
Raw RO/DI water as stated earlier in this thread it is hard to read PH because there is nothing for it to read. Pure RO/DI water is an insulator and does not conduct electricity. Some motors have it inside the motor to keep it cool when they are used to run pumps that pump very hot water in fossil fuel power plants. You do not need to buffer it before adding your salt, it is after adding the salt, then you make any adjustments to it.

 

[rgfast]

thanks Bob

 

[BobBursek]

Your Welcome!!!!