pH of mixed salt water...

dreaminmel

dreaminmel

New member
Now mind you I haven't had any coffee yet today buy I think I've figured out my low pH problem...

So I just did a water change and just about had a heart attack when my digital pH monitor went from 7.9 down to 7.4!! :eek1:

I quickly mixed up and added some of Seachem's reef buffer and now the pH in the tank is at 8.3 and all looks just fine. No cloudiness or anything. (My carbonate alkalinity has also been low so I wouldn't expect cloudiness anyway... I think)

So I had saved two samples of water to test where my silica is coming from for sure anyway. One of the deionized water then another after adding Reef Crystals salt to the bucket to get to 1.026 salinity.

Both samples are testing at out at 7.4 pH! Am I losing it? I thought mixing salt into the water was supposed to bring the pH up to make it correct for going into the tank?...

My test kit is accurate and always matches my digital pH monitor's readings so I'm thinking I have a bad bucket of salt?

I'll be back after I run the whole gamut of tests to post more info...
 
High calcium levels and silica are both also figured out now...

Both tank and newly mixed salt water are testing out at 580 for calcium and my silica is coming from the tap even after being deionized... 1ppm.

So my salt batch is basically only mixing to 7.4 on pH and up to 580 on calcium... grrr.

Will a RO/DI unit remove all silica from my water if I start saving the $$ for one?
 
That's odd....I just tested some fresh Reef Crystals. I made a gallon of water at 79 degrees, and the pH came out 8.2 and the calcium was around 500ppm. I don't have silica test kits, but I had my RODI water tested for silica a year ago and it was undetectable.

Is your newly mixed water well aerated?
 
The SG of the gallon I made was 1.024, so it makes sense that my calcium level was lower than yours but the pH is odd....
 
Definately well aerated. Measurement taken right after vigorous mixing procedure... aerated enough to make my arms sore from shaking and stirring. ;)

My current 160 gallon mix bucket of salt was purchased from Drs. Foster & Smith back in January or February which is when my sever pH issues started to happen. Guess I'll have to buy a new bucket to verify this one's an issue.
 
I've always bought my salt from F&S as well. I think this bucket was from a few months ago, but I'm not sure.

Have you had anyone else check your pH? Is it possible your pH monitor needs a new probe?
 
My Reef Crystals usually make some really high ph water which comes down after I areate, so I am guessing that you have an input problem from your source water. My new RO/DI filter should be in later this week and I will have the 25GPD RO/DI filter that I have been using available for sale if you are interested. The membrane should be due for replacement soon though, so consider that.
 
What brand is the unit? I was looking at the Kent Marine Deluxe Maxxima 35 Hi-S which is pretty nice. Includes a liquid filled pressure guage, TDS monitor and clear canisters. I really like it but know it'll take me about a month to save the cash for it.

I've definately backed up that my pH monitor and pH test kit are getting accurate readings so it's not the test results that are off. I've used Reef Crystals for years now and never had a problem with my pH until this current bucket.

I've already got to buy a few gallons of water from WalMart at some point as I can't use my tap anymore w/ the silicate readings at 1ppm. Hopefully this issue will end once I actually do get a RO/DI unit. :)
 
The filters are by omnipure. Price check a new system though. e-bay has some outstanding prices. That is where I got my new system from.
 
Yeah, unfortunately saltwater chemistry isnt quite that simple :)

On any source of water that has low pH you need to measure both the calc and alk. If one or both is low (regardless of how high the other is) your pH can crash like you're seeing. In your case you say you have a calc of 580 which leads me to believe that your alk is probably VERY low for such a low pH. When your calc and alk are both where they should be, the pH should be there as well. All of those parameters are related.

As for the RO system; as long as its membranes are operating properly you should have no silicates in RO water. I also agree to check out ebay for RO systems, or to ask here. I got a bunch of offers when I was looking for one just last week :)
 
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