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how to raise ph

Andy Pierce said:
Try measuring alkalinity (KH). That is much easier to measure reliably than pH and there is a direct relationship between the two. If your pH really is 3, then a small drop of bromothymol blue (one of the typical reagents used to measure KH) added to a small amount of your tank water will instantly turn a very bright yellow. I use this alkalinity kit from Hanna. Seems pricey but worth every penny (at least for me it is). I really really encourage you to NOT try to raise your pH until you're 100% certain you need to. Your Lincolnshire water, like my Cambridgeshire water, is going to have an alkalinity out of the tap of around 14 dKH (250+ ish ppm). Your 80/20 RO/tap water drops that by a factor of 5 to around 3 dKH (50 ppm). That sets you up for an equilibrium pH of around 7.0 (give or take a little) in a typical indoor room setting. Nothing you describe as in your tank can shift the pH to the degree you're describing and certainly not in the rapid timeframe you're observing.

Get some el-cheapo pH test strips and see what they say. They're not super accurate but the will definitely show whether you pH really is as low as your other method thinks it is.
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my kh reading is 1 from my tank
 
dw1305 said:
Hi all,
You can't really measure the pH of RO water, theoretically it should be "5 and a bit", due to dissolved CO2, but realistically it could give any value. @Andy Pierce can give you the science.
Cheers Darrel
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The key question is what does your meter say the pH of properly made up pH calibration solutions are with known pH 6.86 and pH 4.01 at 25C? These are super cheap to pick up and will give you definite answer on your pH measurements. The inability to accurately measure pH of RO water is in part is why these calibration solutions exist. If you message me your address I'll post you over a couple of sachets of pH calibration powder (to be dissolved in 250 ml RO water before use).
 
Little said:
To get a drop of this magnitude in that time (pH from 7 to 3 in 30 mins), you would likely need to add a strong acid, like hydrochloric acid, sulfuric acid, or nitric acid.
So I guess it sounds more reasonable the reading is somehow faulty / something is impacting the reading somehow?
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What could that something be? and is there anyway to find out? nothing has been added or removed in about 18 months
 
john6 said:
What could that something be? and is there anyway to find out? nothing has been added or removed in about 18 months
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I have no idea. Darrel and Andy are much smarter than me and look like are trying to help you. My post was to back up the theory the water is not actually going from PH7 to PH3 in 30 mins. Thats like water turning from milk to apple juice.
 
Andy Pierce said:
The key question is what does your meter say the pH of properly made up pH calibration solutions are with known pH 6.86 and pH 4.01 at 25C? These are super cheap to pick up and will give you definite answer on your pH measurements. The inability to accurately measure pH of RO water is in part is why these calibration solutions exist. If you message me your address I'll post you over a couple of sachets of pH calibration powder (to be dissolved in 250 ml RO water before use).
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Sorry missed your post.
Thank you for the offer but I have calibration fluid. in 4.01 it reads3.63 and in 7 it reads 6.55. so even at .4 out my tank reading would be 3.5. but I reiterate, my concern is what is causing my ph to drop, not how accurate my ph pen is. If it is impossible to have a drop like that then what could cause my reading to be so inaccurate.
 
john6 said:
If it is impossible to have a drop like that then what could cause my reading to be so inaccurate.
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pH is just really difficult to measure accurately even with high-tech expensive kit. Just for some perspective when I drop my Cambrigeshire tap water pH from 8.3 to about 6.5 (inferred from alkalinity measurements) I do it by adding a pretty good slug of reasonably concentrated hydrochloric acid. Your setup looks pretty typical and you were really stable for 18 months so I really suspect that what suddenly happened is your pH pen broke - really not that unusual actually.
 
Is the pH reading measurement (assuming an electronic meter) being made in the tank or are you taking a sample of water from the tank and measuring away from the tank. If the exaggerated reading is taken in the tank I’d suggest there’s stray voltage present in the tank and it’s messing with the readings. I would check for stray voltage if you have a multimeter as it could indicate a piece of equipment may be failing.

🙂
 
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