Looking For Advice On A New Filter

Whilst externals are undoubtedly better for 200 litre tanks, there are a couple of good internals that would do. These are the largest size of both Fluval U series and Eheim Biopower. You could get two internals under your price limit.

An external doesn't have to be new, second hand ones can be picked up on Ebay, though with used filters it would be a good investment to replace the seals with new ones.
Bear in mind that with the majority of externals the flow rate quoted by the manufacturer is without media inside the filter. As soon as you put the media in, the flow rate drops and this can be quite a lot in some brands. The exception is Eheim, which quotes flow rates with media in the filter.
As I only have internals I'll have to leave it to external owners to recommend a model 

When you do change filters, just put all the media in your current filter into the new one. Sponges can be cut up to make them fit. This will preserve all the bacteria in your current media.

How about this: https://www.amazon.co.uk/Eden-External-Aquarium-Filter-521-200w/dp/B00F93OQ9Y

It's what I plan to use in my 140litre whenever the negotiations are complete in my household as to when we should upgrade the tank (bit like climate change talks here at the moment...)

It has an integrated heater so no need to have this extra piece of kit in the tank

@Andy the minion

Thanks! These All Pond Solution filters look good and much cheaper than the Fluval ones!

Would you definitely stray away from the UV ones?

Its just I had a huge problem with green water a few months ago, trying everything to get rid of it, the only solution I found was a cheap little UV fiter I bought from amazon and its done absolutely wonders for my tank.

Although the water is still a slight tint of green, I can see the back of the tank now  lol.

tbh I woudn't mind doubling up on the UV if possible so was considering this one:

https://www.allpondsolutions.co.uk/aquarium/filters/external/1000lh-9w-uv-1000ef-plus/

@Andy the minion

Thanks, decided to just go with the external filter on its own for now and see how I get on.

looks like it'll arrive tomorrow

exciting!

Great to hear your update and the positive experience you've had.

Typical re the filter price reduction - keep a list of things you want/need, avail of a sale next time round, and it might consequently reduce the 'sting' a little.

Congrats on the pregnancies.
 

Oh, the joy of having a day off work to finish setting up a tank. It's something that I like to do as well.
@Andy the minion I agree with the "before and day after water change" testing to get an idea of how the tank is working. It doesn't have to be forever, but it provide a lot of useful information, and is also useful if big changes are made to the tank (lots more plants added, etc.).
@HalfY it's always worth having a spare filter for so many reasons.
Many congratulations to you and your guppies.    I look forward to hearing updates and hopefully seeing some pictures of tiny blobs of adorableness in the future. 

I admit that my plants are strictly low tech - slow growing plants that don't need special lights, CO2 etc - though I do use Seachem Flourish (comprehensive). I don't run carbon and haven't for years. The main uses for carbon are removing the brown colour from wood and removing medication after treatment has finished.

Carbon adsorbs organic chemicals - that is things that contain carbon, except carbonates. If the minerals in the fertiliser are bound to organic chemicals, than carbon will adsorb them. For example, most dechorinators bind metals using the organic chemical EDTA. Carbon will adsorb the metal-EDTA complex. This is the most likely route for carbon removing trace metals in fertiliser.
I've been looking for the ingredients of EasyCarbo but all I can find is someone saying that someone else said it is the same ingredient as Flourish Excel. If this is true, it contains glutaraldehyde, another organic chemical that will probably be adsorbed by carbon.
And don't forget that carbon becomes full and stops working in anything from a few days to a few weeks. This is why carbon is just about the only filter medium that does need changing regularly. (Filter floss does as well but only because it falls apart if you wash it)

Ceramic rings are indeed a good home for the bacteria.



You could always take the carbon out and keep some in the cupboard just in case. I know that a lot of people with externals use the space where the carbon should go to keep media for an internal filter so it is always ready if they need to set up a hospital or quarantine tank.

Just a little update on the guppies.

We now have 11 fry swimming happily in the tank. One mother gave birth to 5 fry which have grown considerably in a week, two of which have already developed dark colored patches and will probably be males according to some of the articles I've read.

and the other day another another mother gave birth to 6 fry

We still have 2 more pregnant females in the tank, one of which looks like she could pop anytime soon.

May have to ask santa for a new tank lol

Look at the anal fin of the fry - that's the one underneath just in front of the tail. All fry have a fan shaped anal fin until puberty. Then in males it starts to change into a gonopodium. The first ray of the fin will start to elongate, then the rest of the fin will start to shrink. If you want to separate the male fry before they can impregnate both the adults females and the female fry, take them out as soon as that first ray starts to elongate.