Minimal KH in water supply add crushed coral?

thank you, that's a bit of a trek out for me as I'm in Harrogate but I'm wondering if Pet Safari in Otley might stock it. They might do so I'll have a look next time I go

Felt that I had to half the quantity I had in (don't want to be too near neutral), so now down to about 100ml (not very much at all). Through a 25% water change the water arrived at: pH 6.0, gH 5, kH 2

Feeling more in the safe zone, but keeping an eye on things

so is it maintaining the Kh2 now or is it fluctuating?

There doesn't seem much fluctuation on that score, kH 2 (changes to yellow on 2nd drop) has been quite constant (never going to the 3rd drop or reverting back to yellow on first drop). It's possible it was lower than 0.5 when I started, but I soon noticed a change to 0.8.

Just for reference:
If you want to 'drill down' a 1st drop yellow kH reading to find out how low it really is, you can do it as follows:

Step 1.
If the kH was under 1 (Yellow on first drop with 5ml to 1 drop). (go to Step 2 to test further)
If it turns blue you have >1 dH, continue dropping until yellow, counting the drops as per included test instructions, each drop = 1 dH. End of test (don't go to step 2 or 3).

Step 2.
The test kit doesn't tell you this, but:
By adding another 5 ml of aquarium water (so you have 10ml to 1 drop) if it stays Yellow you have <0.5dH (go to Step 3 to test further)
If it turns blue you have between 0.5dH and 1dH. End of test (don't go to step 3).

Step 3.
The test kit doesn't tell you this, but:
If you now remove 5ml of the yellow mixture, you will have (5ml + 0.5 drops) remaining and by adding another 5ml of aquarium water, if the result stays yellow you have <0.25dH. There is not much point adding a step 4, the kH is dangerously low and needs increasing anyway. End of test.
If it turns blue you have between 0.5dH and 0.25dH. End of test.

There is an alternative way to calculate between 0.5 dH and 1 dH, but I haven't done the math for it yet. Oh hang on...
If you do a 5ml 1 drop test and find yellow:
Add 1ml of aquarium water (6ml total), if blue 0.9 dH else:
Add 1ml of aquarium water (7ml total), if blue 0.8 dH else:
Add 1ml of aquarium water (8ml total), if blue 0.7 dH else:
Add 1ml of aquarium water (9ml total), if blue 0.6 dH else:
Add 1ml of aquarium water (10ml total), if blue 0.5 dH else (still yellow there's less than 0.5dH)

Brain doing overtime! Ignore if too complicated.

meh it's too early for my brain Dean .... I'll try and digest that at a later date

It's one week since my last post, things are the same: pH 6.0, gH 5, kH 2
So everything is dandy using about 100mls of coral gravel.

Is it maintaining the kH or is it fluctuating?
Week to week things are stable, pH 6.0, gH 5, kH 2 (yellow on 2nd drop) - as above.

What happened through a 25% water change today?
Despite the fact that I'm adding water with a pH as low as 5.0 to 5.5 - there is no noticeable change in pH or gH at all - however the kH is < 1 on a 5ml test (yellow on 1st drop).

Ignore this bit if it will blow your mind lol: By adding another 1ml of water (so that I have 6ml) it turns blue (In my estimation, that's a kH 0.9 reading).

Am I worried?
No, I expect to get a kH 2 (yellow on 2nd drop) within about 24 hours. This just means it's between 1 and 2, which as I have been advised is okay. Also, I don't expect it to jump up to 3 within the whole week.

So... yes, there is some minor fluctuation through water changes (there has to be some fluctuation) but nothing significant.

it sounds like it's all going well Dean. I'm gonna have to keep my eyes peeled for some of this gravel.

My tap water comes out nearer to neutral (it varies a bit but it's about pH7 to 7.4 depending on when I test) There is something in my tank that is making my water drop to pH6 - it could be the bogwood, I know my sand is lowering the pH from doing the experiment I did last year. It could be organics too. What ever it is is irrelivent - the 'problem' it there and that's that.

For my part it would be easier if I could get my tank pH closer to my tap pH. Water change wise it would be better. I've not checked my kH for a while ... I'm really lazy at checking my water unless I spot a problem! But I'm best guess would be that nothing has changed much. Perhaps I need to check to see if the ocean rock has done anything

Worth checking, things might be a bit better than you thought.

Yes things are fine, the angels will be spawning for the 3rd time in a couple of days. So far 1 hit, 1 miss. The fry are almost 1 month free swimming and have developed well in similar water, most reaching 1cm in length now. I still have 100 of them so they're all relying on me to give them good water. They've eaten me out of house and home!

my female is looking very plump so I think she's about ready to spawn again. Better luck this time for me!