Why don’t you try the flipper it has worked very well for me doesn’t scratch glass (unless you get into the sand then you have a higher chance of scratching) the magnet keeps it at a perfect level and when they go on sale you can get them cheap i purchased 2 for 2 of my tanks and i love them
The flipper max is awesome and the best magnetic cleaner out there. But it's 80 bucks, and while great for in between quick cleaning, still not as thorough as getting your hands in the tank with a razor and getting some muscle behind it.
he doesn’t need the max he needs the regular and at $40 its not bad i got mine from brs for $31 on sale
And as themeat said you will need to get your hand wet every once in a while but its well worth it does a amazing job