Partial water changes should be once every 1-2 weeks, when you're cleaning the filters.

Is that nitrate from the water company? If so it's basically zero. Mine comes out the tap at around 40.

The good thing is that water changes with near zero nitrates makes it much easier to control the nitrate level in the pond.

What volume is the pond and how big are the fish on average? That will determine how big water changes need to be. (Or a larger amount less often)

With regards plants, the faster growing the more rapidly they'll pull nutrients out of the water. Hornswort is great for that, but you'll need to keep thinning it out 

I read the wrong thing on the water website, it's 12mg/l average nitrate.  But still fairly low then.

I don't really know how big it is, about 6ft by 3ft, and 2ft deep, but it's curvy rather than square so hard to work out.  The fish were won at a fun fair many years ago and have just bred ever since lol.  I suppose the biggest are about 6" long.

It's probably best just to stick to the usual 10% per week for a pond. You need to treat the tap water though. It's easier with an aquarium as you can use buckets and just treat the new water. Otherwise you have to treat the whole volume.

If it's had no regular water changes then there is probably really high nitrate levels already present. You can test for these yourself with test kits.

That and other built up compounds will be what the algae is feeding on.

A lot of sunlight will promote algae growth. You could find something to restrict most of the light from getting to the pond

I highly recommend this dechlorinator. The packaging looks different now but its called seachem prime. A cap full treats 200 litres (so just a few drops of a bucket of water) so this will last long. I've had this bottle for about 4-5 years. 

Just now, zain611 said:

I highly recommend this dechlorinator. The packaging looks different now but its called seachem prime. A cap full treats 200 litres (so just a few drops of a bucket of water) so this will last long. I've had this bottle for about 4-5 years. 

Great stuff that I use it too. I couldn't get my first tank to cycle until I switched to seachem prime and stability.

25 minutes ago, alexp999 said:

Great stuff that I use it too. I couldn't get my first tank to cycle until I switched to seachem prime and stability.

Can't you seed the tank using the media in your 200l tank? That's what I'm planning on doing hopefully when I get the next tank. I might cut a fifth of the sponge off and transfer it to the new tank. I have some spare sponge so use that as a replacement. I've managed to get pictures of shrimps. The water is a little dirty because I opened up the filter to partially block the inlet with wool as I was worried the velvet blue shrimp might get sucked up. Luckily though the strength of the  filter doesn't seem to be sucking in a lot. 

Just now, zain611 said:

Can't you seed the tank using the media in your 200l tank? That's what I'm planning on doing hopefully when I get the next tank. I might cut a fifth of the sponge off and transfer it to the new tank. I have some spare sponge so use that as a replacement. I've managed to get pictures of shrimps. The water is a little dirty because I opened up the filter to partially block the inlet with wool as I was worried the velvet blue shrimp might get sucked up. Luckily though the strength of the  filter doesn't seem to be sucking in a lot. 

I have put some media and water across but it still takes time. Just speeds it up.

I've got no ammonia in the second tank now, just waiting for the nitrite to drop to zero then I'll move the danios and turn up the temp on my main tank.

1 minute ago, alexp999 said:

I have put some media and water across but it still takes time. Just speeds it up.

I've got no ammonia in the second tank now, just waiting for the nitrite to drop to zero then I'll move the danios and turn up the temp on my main tank.

That's good. Non of us have the patience to wait for a tank to cycle 

2 minutes ago, zain611 said:

That's good. Non of us have the patience to wait for a tank to cycle 

That's what I mean. The 200L took ages. It wasn't until I switched to seachem prime and stability that it actually started cycling properly. I lost a few danios at the start because it wasn't ready.

That and they are suicidal finding their way in to the original filter housing.

4 minutes ago, alexp999 said:

That's what I mean. The 200L took ages. It wasn't until I switched to seachem prime and stability that it actually started cycling properly. I lost a few danios at the start because it wasn't ready.

That and they are suicidal finding their way in to the original filter housing.

When I started cycling my tank I had a few guppies along with 2 amano shrimps and 2 glow light tetras. From the duration of the start and end of the cycling I'd say one fish died. Months later (I'd say 6 months to a year) the guppies died. The glowlight tetras lasted a while where one lived to around 2 years. Its been 6 years since the tank has been set up so hopefully there's a lot of bacteria colonised in the filter. One of the amano shrimps disappeared. I don't know if he got eaten by his friend and I mistaken his body for a molten skin. The other shrimp is living happily till now. I'm surprised as people say their average lifespan is 2-3 years but this guy has been living for around 6 years. I don't think I'll be getting fish till the next tank as hopefully a school of fish won't be over the stocking limit like with my tank. 

Im definitely also going to take note on the seachem stability. I had stress zyme but that's now out of date. 

I've learnt how to do fishless cycle now anyway and with the bit of media and water from the other one it's not too long a wait.

I’ve got a tank free to anyone who wants it. Will need a good clean as it’s been in the garage a couple of years 

1 hour ago, Philf1 said:

I’ve got a tank free to anyone who wants it. Will need a good clean as it’s been in the garage a couple of years 

What size is it

30”wx12”dx15”h

also have gravel and other bits but as it’s at the back of my garage I don’t really know what is still there 

4 hours ago, Philf1 said:

30”wx12”dx15”h

also have gravel and other bits but as it’s at the back of my garage I don’t really know what is still there 

It's still a little early for me to decide. I've plans go forward to get my room refurbished then but I also like to do my research. I've been looking at one fish tank and luckily saw it in person in a fish shop I visited. 

So went today and picked up a aqua one aquastyle 620T. Really happy with it and also comes with the filter media in the box. Planning next month to set it up. 

 

This was the display one I'd seen few months back. 

 

Opened it up and all looks good. This tank is discontinued so must of been sitting in the shop for a while. Parts are easily available so doesn't put me off. 

Got the cabinet from the same shop. The cabinet which was on the display tank shown above had a lighter wood and black doors. This one has a slightly darker wood which I wanted so it hopefully matches the new cabinets which are going to be made for my room. Might change the doors to match the colour theme. They didn't have any more of this colour cabinet so just got the display one which is in good condition thankfully. There's a little chip on the back corner but little to notice. 😊

Also got some zebra danios. Asked for 4 and got 5 lol. Want to increase the bioload in the current tank so there is a lot of bacteria in the filter to transfer in the new tank hopefully so its a little easier for cycling