Complete newbie and clueless!

[LookoutTrout]

I have the same, my PH is higher than it should be for the hardness and I've never found an explanation.
CO₂ lowers PH without lowering hardness but that doesn't do much to explain why PH is higher than it should be. It might just be my test kits are a bit off, or somewhere along the line someone printed a mistake and it's repeated continuously.
You won't find a huge amount of verifiable science in the fish hobby, there have been some good experiments run but most of them are flawed. The original experimenters usually point out the limitations but they get ignored when people quote them later on. If you want better science look to aquaculture and sewage processing but their testing only goes so far to help us.

[Vale!]

I wasn't going to return, but this ...

... seachem aquavitro.

... drew me back briefly to make this comment. This is your first mention of using a product from Seachem's 'Aquavitro' range, designed for marine (seawater) tanks apparently - I had to look it up!

Which one of the range is it - what does it say on the bottle? Is it a recent addition? Was it sold to you along with the Platys by any chance (just a gratuitous shot in the dark there!)?

[Edit: to acknowledge LoT's interposed post]

[fr499y]

They do Aquavitro for freshwater too. I could be mineralize which is designed to up the hardness of the water or even carbonate which will also increase the hardness.

[Titchyfeep]

I wasn't going to return, but this ...

... seachem aquavitro.

... drew me back briefly to make this comment. This is your first mention of using a product from Seachem's 'Aquavitro' range, designed for marine (seawater) tanks apparently - I had to look it up!

Which one of the range is it - what does it say on the bottle? Is it a recent addition? Was it sold to you along with the Platys by any chance (just a gratuitous shot in the dark there!)?

[Edit: to acknowledge LoT's interposed post]

It was given to me by the lfs- it was a small quantity not in the original bottle and had hand written instructions for dosage. the hand writing wasn’t the best but it did say seachem aquavitro but I know there are numerous versions. I hadn’t bought any fish when it was given to me, I hadn’t even mentioned a possibility of getting platys at that point. I had told them my plants had melted even though I thought it was my fault for not having the light on for long enough. They gave me replacement plants along with the aquavitro.

[Vale!]

They do Aquavitro for freshwater too.

Thanks, M. I added 'freshwater' to my original search string and a different set of results was returned.

[black ghost]

Ignore pH, it’s not important to most fish. The hardness IS important. Can you remind me what the hardness is…?

[Vale!]

Native tapwater averaged 0.89dGH German and KH 0.88 last year. Conductivity averaged 55uS/cm.

We don't know what these values are in-tank.

[black ghost]

So, extremely soft? It’s impossible to keep Platies or any of the common livebearers healthy in that.

[Vale!]

I think this is from the second post in the thread, way back when :

You're in Scotland I think? Your tapwater is probably 'soft' so that knowledge will help choice of eventual fishies : platy, for example - bad ; betta and neon rasbora, for example - good, except a hungry betta probably means shrimp only for a short time!

But naturally a family-run and favourably-reviewed LFS must know better. It's no wonder that LFS's and internet forums are at each others' throats much of the time, with new hobbyists such as Tf caught in the crossfire.

[Titchyfeep]

I think this is from the second post in the thread, way back when :

You're in Scotland I think? Your tapwater is probably 'soft' so that knowledge will help choice of eventual fishies : platy, for example - bad ; betta and neon rasbora, for example - good, except a hungry betta probably means shrimp only for a short time!

But naturally a family-run and favourably-reviewed LFS must know better. It's no wonder that LFS's and internet forums are at each others' throats much of the time.

I’m sorry that you feel that way and I didn’t intentionally ignore anyone’s advice. I hate that people think badly of me because I don’t retain information. I will be 100% honest and say I didn’t recall that post when buying the fish. It’s very difficult for me to not accept what’s being said to my face by the person stood in front of me. In hindsight I should have walked out the lfs without anything. If it wasn’t completely obvious by how I come across in prior posts I have ADHD. I should never have attempted fish keeping. Tbf I never said the fish shop knew better and I have clearly said I was overwhelmed.