Shrimp tank water chemistry

[Lev]

So, my 20L planted shrimp tank which is fully cycled but fairly recently occupied my shrimp (4 days!) seems to be going well so far. But I have a question about the GH and KH.

I only just started measuring these (oops) and I note that my flora base pro substrate is keeping the pH nicely at 6.5 but when I tested the KH yesterday it was <1DH. After a water change (50% as an experiment) today the pH remains 6.5 and the KH is now 3DH which still seems quite low (ie are my shrimpies getting pickled at night time??)

Tank:
pH 6.5
GH 5DH.
KH 3DH
Nh3 0
No2 0
No3 5ppm

Tap water:
Ph 7
GH 9DH
KH 4DH
Nh3 0
No2 0
No3 0

The substrate is flora base pro.

Should I be adding some sort of buffer to prevent pH spikes at night when plants respiring and if so what?

Here's a picture of one of the inmates because reasons.

 

[TMaier]

Inmates?! [emoji23]

 

[Lev]

By pH spikes I mean pH dropping off overnight sorry for misleading lingo + my phone won't let me edit post

 

[Lev]

Inmates?! [emoji23]

They explored the edges so much when I added them i could only presume they were trying to escape! [emoji23]

 

[flchamp89]

Are you saying it's swinging .5? If so I wouldn't be concerned at all

 

[Lev]

Well I suppose what I need to do is see what the pH actually does at night by measuring it at night

The 0.5 difference is between the tap water and water in tank (which I presumed is due to substrate which claims to hold ph around 6-6.5) my query was whether the low KH means the pH would drop off <6 at night. I guess there's only 1 way to find out!

 

[flchamp89]

If you take ph in early morning before lights are on that would give ya an idea.