Thank you for all the responses and the advice. I have ordered connector/ reducers from e-bay.
Some background - started in August with a test tank with the following equipment on a 60 x 30 x 45 tank:
JBL CristalProfi E701 Greenline External Filter ( 700 l/h)
12mm Glass Lily Pipe with glass skimmer inflow
The light is a 39W 117 PC Led 5800 Lumen , 8000k 'ADA' style
Turbo CO2 Reactor Diffuser
After posting this on the forum and following the advice I got this tank going, sorted the algae issues and demonstrated to myself that I could actually manage a tank - with an inline diffuser.
Three weeks ago I 'graduated' to 70 x 60 x 45 tank (189 liters). I am waiting for my new Chihiros WRGB light to arrive for this tank and in the interim wanted to declutter by using a inline heater - hence my post.
I do realize that I need to upgrate my filter to increase the flow to X10 so bought a Hydor 300 filter from e-bay, however, realized that it was too noisy, probably not the best one to go for, it also didn't have any filter media (note to self read the small print) and it would need a new glass lily pipe and skimmer...
The new larger glasswork is in the pipeline (pun intended) and I intend - at some point in the near future - after I have found a buyer for a non-essential internal organ - to buy a new filter with a bigger capacity. At the moment I am sticking with the JBL CristalProfi augmented by an old internal filter to ensure that I have the right amount of flow. In the interim I drinking white wine, listening to Nils Frahm and looking at filters. Perhaps a Aquael Ultramax 1000 in the January sales? Does anyone have any advice?
PS anyone want to buy a slightly used JBL filter with a Hydor 300?
Pictures of of the new tank are below. This is, I hasten to add a work in progress. I intend cover the lava rock with small epiphytes - just can't decide which ones.
Oh - the tank has a population of agoraphobic green tetras, exhibitionist ottos (with a slight addiction to cucumber) and cherry shrimp.