Strange Red Algae in freshwater tank

[Lovelyfishy]

For the last year I’ve had this strange Reddish Brown Algae growing on my ornaments, bogwood and rocks. It started first appearing on the crocodile ornament, has now spread on rocks and bogwood. Our tank is freshwater, tropical, used to be live plants but now only fake ones, gravel substrate, water changes aren’t as regular as they should be I must admit and I have no idea of the ph etc as we’ve ran out of all our testing kits and due to COVID money is now tight! I can’t seem to find anything similar online to what we have, does anybody have any clue?
It’s not causing any problems that I can see, just curious to know what it is incase it’s causing a problem without knowing.

[TropicalFishForums]