Fitting gauge to plastic water tank

[dgadee]

I have a newish, good quality water tank (perhaps TekTanks) to which I want to add a Weema type 5 hole gauge. What flange fitting should I use to accept the gauge? There appear to be several types out there. There is no access hole in the tank.

 

[dgadee]

No response! I contacted Wema who pointed me to their ss flange. Cheaper than the resellers, too.

 

[Laysula]

I just used five countersunk rivnuts into the plastic.