Timbo

When my tank & pump were installed I had a bright idea. But the plumber had already had the same idea. That is a tap on the municipal line before the tank. You can use that tap all you like. It will work at municipal pressure (when that is present) and will not affect your tank nor cause the pump to run. So use that for, say, garden sprinklers (not that any civic-minded person in Johannesburg would run those whilst the sun is in the sky. Heaven forfend!). 

So the pump only runs when water is used in the house or when the washing machine is on. In our circumstances (2 adults, appliances set for minimal water use) this means the pump doesn't work too hard.

A 1.1 kW swimming pool pump for instance operates at 230V AC with a running current of 4.8A. During startup, the motor can draw approximately  28.7A (6.6 kW) for the first second or two, depending on factors such as temperature, starting angle, load, and other conditions. All HF inverters have a voltage sag if inductive loads are applied for a few milliseconds. The low frequency inverters like Victron cope much better with inductive loads. You could get an external single phase VSD for your existing pump but they are not cheap. Like @JayMardernsaid some led bulbs are more susceptible to voltage changes so your cheapest option might be to try different led ranges.
 

Send @Jaco de Jongh a pm

I just looked at which IP the DHCP server on my router assigned to the Pi (and then reserved that IP for the Pi so that it will never change). It is a bit easier if you don't have a extra monitor and keyboard.
The VictronConnect app will also help with that if it is on the same network.

The VenusOS setup is super simple and it just work. For this setup the only thing you need other than the Pi and the VenusOS image, is to get a 485 converter. If you use a USB-485 (link the link in my post that you quoted) you don't need to do anything extra. You can get a RS485 hat as well, but it has to be setup in the config.txt. This one has a CAN interface as well as 485, but need a bit of setup. You do save a USB port though.

I did this. I got an ET112, installed the VenusOS on the rPi3 laying around and watch for a few months.
You can use any RS485->USB converter (or if you have one already) to connect the pi and the et112, but those will not be galvanically isolated as the Victron cable that you buy for ~R500 (safer option for your equipment in the long run)
After getting all the data, I got my MP II and installed all this alongside the pi and meter. If you want to Color GX option in future, you can just go ahead and rather do that then the Pi from the start. Then everything is Blue and you have all the ports you will need already. I like to give myself some work and fiddle, so the Pi route with hats and RS485 converter was my preferred route.

Sorry about the title - seems to be a forum rib of sorts ?
Anyway here is my install - was quite challenging doing it all myself with little solar experience. Silly things like just getting inverter on the wall (thing ways a ton) , thank goodness for climbing gear and pulleys, made it a steep learning curve. Hopefully the forum wolves will be kind though   .  
System :Victron Inverter  - Quattro 10000va /  Victron 250/100 SmartSolar MPPT /  20 x 330 Watt Canadian Solar  / Victron BMV702  / Revov 10 kWh / Venus GX running ESS  / ET112 Grid Meter / Home Assistant Integration. In case you wondering system is limited that it can’t feed more than 4.6kW into grid.
Things I would have done differently: 
- Bigger fuse boxes & bit more spacing - 35mm2 wire is difficult to bend
- Wider trucking - same reason as above
My average use is 30-35 kWh per day - system is producing 18kWh on average (mid winter) per day - looking forward to summer. The Battery is on paper too small as most use is in evening, however in Port Elizabeth we can Grid tie one to one and we are on Eskom time of use tariffs, so battery only needs to get me through the 2 peak periods, then use the grid as a cheap battery for balance of time.
With the home automation (Home Assistant) tie-in, I manipulate a few things on system via Modibus to optimise the return:
System makes sure batteries are charged for morning and evening peak using grid if needed  - (buys cheaper power or uses credit generated during day). I do this by changing the Grid set point higher for this period. If there is loadshedding (it reads the loadshedding status form Eskom website) - it changes min SOC from 20% to 50% - that way there is enough capacity in batteries to get through any loadshedding episodes regardless of time of day.  Also notifies me of grid failure over google home and on phone 
Pic 1 - Christmas - trying to figure everything out
 
 
Pic 2 - figuring out cable routes - old inverter/ups in green looking sad
 
 
Pic 3 - Old Main Db Board (nice excuse to tidy up)
 
 
Pic 4 - Honey will we have lights tonight ? - no pressure - all stripped out
 
 
Pic 5 - Main Db Looking bit more tidy - split into 2 - Db1 non critical AC loads - Oven and Geyser on Left ELU -  Db3 - Critical Loads -  balance of house - plugs and lights
(Note Inverter feeds back up to DB1 if grid present so DB1 is on Inverter / solar /battery until there is a grid failure)
 
 
Pic 6 - Revov Batteries 10 KWh- server rack box adapted with some additional home made welded brackets (its a 50kg load) - but nicely off the floor
 
 
Pic 7 - DC Buss-bar -  cramped DC shunt and fuse box  - will know for next time - give yourself more room
 
 
Pic 8 - AC DB 2 - feeds to and from Db 1/D b3 with 3 way change over switch (can bypass inverter if its faulty)  - MPPT on left - Solar DC DB &  fuses on right
 
 
Pic 9 - Solar DB - only partly my work that''s why is so neat   - 4 strings of 5 panels  - bottom 2 cables have subsequently been increased to 10mm2 from 6mm2 shown here - MPPT was kicking errors - seems happier now
 
 
Pic 10 - Overview of installation - Inverter quite noisy (I am noise sensitive) - so nice to be in the garage vs in house
 
 
Pic 11 - Colour GX and BMV installed round corner (more accessible)
 
 
Pic 12  - Panels  - 20 x 330W - 4 strings of 5 - 5 deg - facing NE - raised back 5 because of shading
 
 
Pic 13 - Home Assistant Home Automation Tie in - Note loadshedding sensor (still working on overall layout but its 100% customisable)
 

Pic 14 - Municipal Grid-tie meter with ET112 Grid Meter on right