Cool thankyou thats useful
So water hardness usually affects fish in the long term and impacts on their lifespan rather than short term. A molly should live for 5 or so years but in soft water this could be reduced to 2 or less so its just something to be aware of. I'm not a massive fan of suggesting rehoming fish in these instances as the odds are that if you take it to a local store someone else with identical water to you will take them home and they might not be as dedicated to their tank as you are in terms of research and maintenance
But just something to bear in mind in the future with other fish selections.
Is the 75g a 4 foot tank? I believe standard 75 dimensions are 48x18x21 inches does that sound about right? I'm not 100% on those algae eaters they could be the natural colour version of Chinese Algae Eaters which can be quite a problematic fish when they get older and may not be compatible with your angels and goruami as there are reports of them sucking on the side of large bodied fish. Can you get a photo of the pleco? Hoping its something like a rubber lip or bristlenose.
If I was splitting those fish between a 75 and a 29 I would go for something like.
75g
2 Angelfish
2 Mollies
4 Platies
4 Danios
29g
3 Dwarf Gourami
10 Neon Tetras
4 Cories
I'd rehome the Algae Eaters as I think these are going to cause problems in the future and in contrast to the hardwater issues I think they will be better suited to someone else tank long term.
I'm hoping that the 75g will be at least 18 inches tall which is a minimum depth for me for angels as they are a very tall fish when adult as close to 2 foot would be preferable too. A sand substrate would be in their best interest too as it will protect their trailing ventral fins.
In the 75g I would increase the number of danios to around 15 of all the same species and in the 29 increase your cories to 8 again the same species as the 4 you have (if you have Bronze you could get Albino or any of the line bred variants long fin, high fin etc).
Wills