A rare earth magnet no more than a 1/4 inch thick sealed with a super hard plastic that can be used like a magfloat to remove coraline in very tight spots.

Something that would allow safely moving a full tank.

A nano tank 5 -10 gallons display (eg zero reef coral)with a underneath sump, refill, dump water area...water dumbos 70% or so into a 5 gallon bucket so it is humanly possible to lift up and dump. Mixed new water refills at a switch. Water change is a real pain and with the world only going smaller condos, no one can buy 150 gallon tanks and fit it all in a hectic lifestyle.

Ps... you know xreefer iminsky runs tinkerine.com

I second that

There is something like that out there already , hopefully they release it soon.

https://reefbuilders.com/2015/07/27/...e-kickstarter/

I think he ment probes which last more than a month.

I think the idea is cool but at 7-900 up front and 500 a year for discs @ the discounted pricing which im sure are both in USD. It's not a realistic purchase for a lot of people where a $50-70 probe that lasts any length of time I'd buy them for sure.

An auto feeder that dispenses frozen food. I've seen a few interesting DIY jobs involving mini fridges but nothing even remotely compact.

Plasma lighting in the 14K spectrum.

I'll put my hand up too for the Alkalinity monitor.

There are commercial probes for exactly this and they last quite a while... but they ain't cheap ($250+) and seawater can cause them issues. I used to have 5 or 6 of them in my lab (we specialized in electrochemistry) and tried them at home a few times with relative success. I believe Pinpoint Monitoring actually makes a somewhat affordable unit and, if I remember correctly, was reviewed by Randy Holmes-Farley in one of the reefing magazines.

The kicker with these units though is that to get accurate measurements they sometimes need to be paired with a pH probe. The potential (i.e. voltage) of an electrode shifts 0.059V per decade (meaning one pH unit, such as if the pH shifts from 7 to 8). Doesn't sound like much but once that error gets factored in, your measurement could swing wildly with pH shifts throughout the day, talk additions, etc.

So, it can be done but it hit always going to be cheap.

second the frozen food feeder

an adjustable sump system where you can increase or decrease size of the chambers with sliders so you can add or remove equipment and make space accordingly

A fitration system that takes in your dirty tank water and spits out water as clean as the day you made it. The filter would remove all bad items but leave the salt and all trace elements. A true sea water purification system that is easy to use.

It would remove all algae, nitrate, phosphate, pests (ich) and just return water that only had the good stuff left in it.