You could use Poret foam in the corner to cover you heater and water pickup. https://fish2water.com/corner-filter-hmfs.php
I've used these filters in my tanks for 6 years now and never had to clean them and they do help to create a cleaner looking tank.
It also means that for tanks which have canister filter I remove all the foam and add matrix to the filter trays.
Its also rather concerning when you read something like this: Mycobacteriosis Fish Tuberculosis I did not know that high KH would help, I have been keeping my Cichlid at above 10 GH but keeping the KH high has been ready hard.
After keeping a 160L Goldfish tank for 20 years and having had a disease which slowly killed everything.
I decided to up my game and have put together a 500L tank with a 160L sump for African Cichlid's (Early 2015). This turned in to a rack which is 300L and a four foot 200L tank end the end of the year.
I hope these photos will be a record of my time with these fish.
Mike