My 240l Planted Tank, Again.

There's a lot to be said for low tech, low maintenance tanks. 
I've found that crypts do quite well for me too.
Your set up looks great, and your fish look really happy with their environment. 

My kuhlis are pretty old.

The last time I bought kuhlis was before I had any children (or even a bump). It was in winter and I think they got too cold on the way home. Anyway, whitespot developed and wiped most of them out. These two are the last survivors, though at least 3 survived the whitespot.

 My daughter is nearly 6, so they could be 8 years old! I don't think they get on particularly well as I rarely see them sharing a space and they certainly don't wrap up together as you see in the shops. I can't really tell, but I think they may both be females.

It is also possible that at least one of the was 'born' in my tank, because when I had half a dozen, I remember suddenly seeing one that was significantly smaller than the others. I have always struggled to count them, because there are so many places to hide in my tank and they never all come out at once. So maybe they're not as old.

Perhaps I have more than 2, but I've only seen 2 at the same time for a very long time.

Helen, what are the small patches I can see, which obscure the vision a little....?  I'm colour blind and can't tell if it's something that's supposed to be there or if the tank glass could do with a scrape...

Interesting...  As you know, I'm colour blind but even so it still doesn't look like algae...  I wonder if it is indeed some sort of deposit from fertiliser, as you suggest... 

I was looking at your Seneye output Helen. What timescale are the readings over ? I can’t see the bottom scale on the pic.

When you have young children that are cute enough to be given free things and a birthday in late January when the fish shop is clearing out its Christmas stock...