Weird water help: low kH

VikingMummy2015

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4 Jul 2020
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Scotland
Hi.
I’ve recently discovered that my tap water has gone from regularly being 6.4-6.6 to now being 7.4-7.6. However, I only have a kH of 1-2 (API kit, 1 drop is a faint yellow).
I have always known about the low kH so always do two water changes per week (roughly 20-30% each time) to keep it stable (tank pH has always been 6.4-6.6 for the past 2 years). Except now that the tap pH has changed and I have huge pH swings over 24 hours. i’ve already lost a honey gourami, and the pH is the only explanation.

I just can’t get all my tanks behaving the same way and it’s stressing me out trying to keep them all healthy!

T1: Tropica soil, redmoor wood, 29L, lightly to moderately planted (dwarf sag, Amazon swords, Anubias, java fern, salvinia) housing a Betta and a Nerite snail. Roughly 40% water changes twice weekly, pH holding at 6.4-6.6 even after water change with 7.4 tap water.
T2: 57L Fluval, Tropica soil, dragonstone, smaller amount redmoor, moderately to well planted (hellanthum tennelum, lobelia, bacopa, hygrophilla, crypts, ludwigia, bucephelandra, salvinia and Anubias) housing 8 cherry barbs and 2 honey gourami. Dose every other day with Aquascaper liquid ferts 1ml. pH holding around 7 between water changes.
T3: 54L, Tropica soil and black sand (all pond solutions, previously in what is now T1) with dragonstone. Moderately well planted (staurogyne repens, ludwigia, lobelia, crypts, bucephelandra, rotala, hygrophilla, salvinia, Anubias and a Dennerle Anubias driftwood tree). Not yet stocked; fishless cycle using Stability and liquid ammonia was completed and then wobbled last week. pH bottomed out at 6 yesterday despite water change 2 days prior. 24 hours after an 80% water change with pH7.4, it’s reading 6.6. Covered in brown diatoms.

I daren’t stock T3 until I can figure out how to keep the pH stable eg raise that kH but not raise the pH further! It’s unusual to have a pH above 7 with a kH as low as 1, I know (but that’s what all Scottish water reports give for my area). So I ideally need to buffer the kH but not raise the pH. I’ve heard of people using Seachem alkaline and acid buffers together? But I can’t find any answers for this type of situation. I’m not trying to chase pH or raise/lower it per say; I need it to just stay stable in the tank at a value...not fussed if that’s 6.6 or 7.6 particularly! The gH is 2.

I hope that makes some sort of sense! Photos of each tank (T1, T3, T2) 940F8138-8127-4838-B38D-223409C35B36.jpeg6E63A146-4482-4BAD-BA02-1064BC862174.jpeg56B23620-727C-4667-AF3E-552F427953D8.jpeg
 

X3NiTH

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13 Apr 2014
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997
You can source and use Potassium Bicarbonate to increase the KH, for the pH balancing hydrogen donor you could add some wood or if you want something similar out of a bottle then JBL Ph Down is an oak leaf extract and quite effective.

:)
 

dw1305

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7 Apr 2008
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nr Bath
Hi all,
Why is it added to water?
Just to <"raise the pH">, if you have alkaline water in doesn't dissolve any lead (Pb), copper (Cu) or zinc (Zn) from old pipes and that levels of lead (Pb) will remain below the 10 microgram (10^-9 g) / L statutory limit.

cheers Darrel
 

VikingMummy2015

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4 Jul 2020
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Scotland
I’ve added a small spoon of potassium bicarbonate to T3: after 1 hour the kH was raised to a definite 2 drops (who knew the first drop could be blue?!) and pH had risen from 6.6 to 7.4. Tested pH 3.5 hours later on a whim and already dropped back closer to 7.
 

veerserif

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7 Jul 2020
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Bay Area, California
My tap water is similar to yours, I think - we get water out of the tap at pH 9 but it's actually very soft (~1dKH, 1-3 dGH) and settles at pH 7.4 after 24 hours. And yes, it's because they add lime to the water. I keep crushed coral in my tanks to add a little KH, so now they stay about 2-3 dKH. I've genuinely stopped testing pH since it's not a useful measurement in water this soft, as the slightest addition will cause it to swing wildly. I went with crushed coral just because it's cheap, and I originally did it to add calcium for the shrimp and snails. Any source of calcium carbonate would do the same thing.

I would guess that your various aquasoils and driftwoods are what's lowering your pH, as well as continued gas exchange, so I wouldn't be surprised if it takes 24 hours just for your pH to settle on any particular number. Less of a "swing", more that your tank water is settling at its "actual" pH.

Sorry to hear about your honey gourami. I wonder if the pH change in your tap water is a herald of something more serious than "just" the pH change - maybe more chloramines, or a sudden increase in hardness? That is to say, it's not the pH itself that is the problem but whatever caused the pH swing. So holding the pH steady may not fix the root issue.
 

VikingMummy2015

New Member
Joined
4 Jul 2020
Messages
8
Location
Scotland
My tap water is similar to yours, I think - we get water out of the tap at pH 9 but it's actually very soft (~1dKH, 1-3 dGH) and settles at pH 7.4 after 24 hours. And yes, it's because they add lime to the water. I keep crushed coral in my tanks to add a little KH, so now they stay about 2-3 dKH. I've genuinely stopped testing pH since it's not a useful measurement in water this soft, as the slightest addition will cause it to swing wildly. I went with crushed coral just because it's cheap, and I originally did it to add calcium for the shrimp and snails. Any source of calcium carbonate would do the same thing.

I would guess that your various aquasoils and driftwoods are what's lowering your pH, as well as continued gas exchange, so I wouldn't be surprised if it takes 24 hours just for your pH to settle on any particular number. Less of a "swing", more that your tank water is settling at its "actual" pH.

Sorry to hear about your honey gourami. I wonder if the pH change in your tap water is a herald of something more serious than "just" the pH change - maybe more chloramines, or a sudden increase in hardness? That is to say, it's not the pH itself that is the problem but whatever caused the pH swing. So holding the pH steady may not fix the root issue.

I think they’re adding more chloramine but asking around locally and within a Scottish group is producing a lot of shrugged shoulders and “well mine are fine”.
All 3 tanks are holding their value now from yesterday. Varies from 6.6 to 7.2 but at least it’s stable.
I did try leaving water out overnight to “settle” and pH didn’t change from tap value. So it’s tank processes that are dropping it. I’m hopeful that i’m On top of it now, and will keep an eye on it very closely over the next week (all parameters). I don’t want to be adding products needlessly because that can lead to more problems than it solves. The only products i’ve Seen that *might* reassure me are neutral buffers but I need to read up more on how they actually work and what they do as they sound a bit too good to be true.
 

dw1305

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7 Apr 2008
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nr Bath
Hi all,
The only products i’ve Seen that *might* reassure me are neutral buffers but I need to read up more on how they actually work and what they do as they sound a bit too good to be true.
These are phosphate buffers, they serve <"no useful purpose in the fish tank">, but do transfer your money (and a very large profit) to the manufacturer.

I use rainwater, but it has a bit of carbonate buffering because of where I live (it is all limestone locally). My suggestion is to use potassium bicarbonate (KHCO3) you already have and add @veerserif 's calcium carbonate source. I like <"Oyster shell chick grit">, mainly because it is very cheap.

cheers Darrel
 

Oldguy

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27 Aug 2018
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Gloucestershire, UK
chloramine

Water supply companies are a little coy about chloramine, especially if they cover a large geographical region with many water sources. It is sometimes added if there is a 'local problem'. Typically added to water abstracted from the lower reaches of large rivers.

For the past ten years my tap water as smelled like chlorine and not like swimming baths (chlorine + wee = chloramines) but I always check after runnng the cold tap for a little time. (chlorine can also migrate overnight to sections of the water distribution network and give a strong whiff when the tap is turned on.

High pH and low hardness are products of treated drinking water. On balance a small price to pay.

I cut with rainwater and then add a few chemicals/minerals to help the plants grow and the fish to be happy bunnies.
 

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