gH and kH management

[A dishy fish]

Looking for advice,

First aquarium and needing some tips for managing gH and kH

30l tank. My tap water is v soft, 30ppm gH and 0 ppm kH
Stupidly put some shrimp in before getting these parameters sorted. Shrimp seem ok so far but likely wont be for too long
Tank has been cycled and looking to get the numbers up.
I have heard crushed coral can be useful but slow and is a good buffer med- longterm.
I intent to keep some shrimp, maybe some otocinclus and some guppies
my current parameters in the tank are gH 30, kH 40, pH 6.5 - 7, nitrate and nitrites 0 (using a test strip)
Fluval stratum substrate

options: 1) i was thinking of building up the parameters by gradually adding coral till getting to numbers I am happy with. One issue I see with this is that my tap water will be a fair bit different to my tank water. Can I just do smaller water changes say weekly (using a basic water conditioner) in order to keep parameters relatively stable? Or will this be too much variability?

Option 2) I have come across a pre mix which alleges to manage kH and gH when used with all water changes. Would this be a more simple option if gradually introduced in water changes?
The stuff I have looked into is "Salty Shrimp - Shrimp Mineral GH/KH+"

Many thanks any please be gentle to this newbie

[Martinspuddle]

Greetings.

Working on the conversion of dividing by 17.86 you get the German scale that means you have a GH 1.6

Yep you got some issues.

Where abouts in our great kingdom do you live?

[A dishy fish]

Scotland, water is very soft up here

[Martinspuddle]

How about we swap, you move down here (Kent) and I'll move up there... My dGH is 17!

Luckily for you soft water is easier to buffer up than it is for me to buffer down. Crushed coral in a filter is one option, most people end up buying a proprietary Buffer and add it in their water changes to keep the GH up and at a reasonable level.

If it was me I build the aquarium up to the level you want and then premix any water for water changes in something like a 25 litre container to the desired GH and pH.

[A dishy fish]

Thanks for the tips, do you mean build it up naturally with coral and then I can use a pre made buffer for changes?

[Fishtales]

As I have fluctuating water, I use Seachem Equilibrium to remineralize my RO water. I also use Seachems Alkaline buffer to give a kh of between 4 or 5. For me this is a good kh number to keep my ph level stable. They work very well so would imagine similar products are effective too.

I think I saw the Salty shrimp products on the pro shrimp website when I ordered my Seachems. I would think it is therefore a reputable product.

[Martinspuddle]

Thanks for the tips, do you mean build it up naturally with coral and then I can use a pre made buffer for changes?

Yes, you can do it that way but just keep an eye on your parameters. @Fishtales suggested using one of those stability products to keep them running in check long term.

[plankton]

Welcome to the forum.
OK.
Your water is currently perfect for otos.
Caradina shrimp will also be ok (crystal reds and similar) with a boost of calcium (like cuttlefish "bone").
Guppies won't be too good though, they need a certain amount of hardness for osmotic purposes, so should be above 7 dGH.
If you want to keep guppies then I suggest two tanks, one for softwater, one for hard.
Or drop the otos if you just want guppies and neocaradina shrimp (red cherrys and similar).