Tap Water v RO Water - My parameters

[AlexT]

I thought it was time to do a separate thread for this. I live in North London, UK. Below are the tap water readings/tank readings. All hardness readings are dH. Tank is still fishless cycling. Small tank, 110 L.

Preferences for stocking; x1 young BN pleco, x12 small Bronze/albino corydoras, x1 Bolivian Ram, x8 Harlequin rasbora, x8 Black phantom tetra. Heavily planted. 2 or 3 decent size bits of wood. Sand substrate.

With the rasbora's and tetra's, I am not decided. Trying to be flexible on this. I have had some nice suggestions from @Byron and @Wills I might look into some other rasbora's. Some of the decisions will be dependant on what water parameters I think I can realistically maintain, hence this thread.

Tap Water readings
Ammonia 0ppm
Nitrite 0-0.25ppm (has been 0.25ppm last few days which can happen)
Nitrate 30ppm
pH 7.5
KH 10
GH 16

Tank readings (70% RO and 30% Tap) - these readings only apply today, prior to today the tank was 50% RO and 50% tap.
I have omitted Ammonia, Nitrite, and Nitrate as it's fishless cycling.
pH 7.4
KH 4
GH 6

Questions & Thoughts
- It's a 110 L tank. I can get the RO quite easily, 30min drive away and I can afford it. £5 per 25 L of RO (I am sure there are cheaper ways, but for now I can afford it). However, I had planned on 50/50 RO and I don't especially want to go above 70/30 RO/TAP because this is the first time I have ever used RO.

- Does pH take longer to come down? Or because I am starting with tap water KH of 10, is the buffering going to stop me getting closer 7.0 pH? There is barely a difference on the colour charts between my tap water pH and using 70% RO. Tap is 7.5 and my tank is 7.4

- Perhaps I should stick with what I've got? Roll with 70% RO, because I think it will be fine for the Corydoras, BN Pleco, and Bolivian Ram, but not so much for the Tetra's (if I go for the tetra's).

- Is it worth trying to get the pH down some more? Would the cost/benefit be favourable?

- If I am only going to stick with this 110 L tank, should I think about a cheap way of using an RO unit at home, bearing in mind no experience? It would have to be something that can be temporarily connected to a tap without under the sink plumbing. Is this possible? Any idea what we are looking at financially?

Thanks all.

 

[Wills]

I think with hard water and nitrate at 30ppm if you can go for RO its a good idea. I have similar water, not quite as high nitrate but close - I've tried RO before and I didnt like it. My answer has been to embrace harder water fish like Myanmar/Lake Inle, Asian mountain stream habitats, Central America and Rift Lakes (Malawi and Tanganyika) but also add terrestrial house plants to the surface of my tanks and allow the plants to root in the water and often into the substrate in the tank. This solved both of the options naturally and simply rather than going doing the RO route which can be a little complex.

If you wanted to go down a hard water route I would look at the Myanmar/Asian mountain stream tank and stock something like

3 Red Honey Gourami (1m 2f)
8 Espei Rasboras or Rummy Nose Rasboras
15 Galaxy or Emerald Rasboras
8 Rosy Loaches or Inle Loaches
5 Amano Shrimp + 5 Nerite Snails

You may also be able to reduce some numbers of the schooling fish and get a small group of some kind of Stiphodon or Sicydium goby as some of these come from the harder water areas - though some species come from more neutral areas.


If you went to the RO route I think your stocking looks good - having just one asian fish in there does something to my biotope OCD so if you can find a smaller tetra that might help . If you can buy RO from an LFS great just make sure you have a stock in just incase you need to do a water change urgently. If you are using RO you may as well get the water as soft as you can as that will benefit these fish quite a bit - home RO units start at about £50 but you'd probably spend that once a year on replacing the cartridges (though still cheaper than buying just the water I suppose). Plumbing it in isnt too hard if you have a place for it and where you can store water - always though a utility room would be best if you have one?

Wills

 

[Colin_T]

you could do 50/50 r/o & tap for a GH around 140ppm, which is fine for the fish you want.

SOLAR STILL
You can make a solar still. It would give you pure water, no waste water and be free to make pure water, it just requires a bit of sunlight.

Get a large plastic storage container and put it outside in the sun.
Pour a bucket of water into the storage container.
Put a clean bucket in the middle of the storage container. Have a rock in the bucket to stop it floating around.
Put the lid on the storage container.
Put a rock or small weight on the lid in the middle, so the lid sags above the bucket.

As the sun heats up the container, water will evaporate and condense on the underside of the lid. The water will run towards the centre and drip into the bucket. When the bucket is full of water, you put it into a holding container and put the bucket back in the storage container with another bucket of tap water.

You get pure water with a pH of 7.0, 0 GH, 0KH and no wasted water, no power used and it's cheap to set up.

 

[Wills]

you could do 50/50 r/o & tap for a GH around 140ppm, which is fine for the fish you want.

SOLAR STILL
You can make a solar still. It would give you pure water, no waste water and be free to make pure water, it just requires a bit of sunlight.

Get a large plastic storage container and put it outside in the sun.
Pour a bucket of water into the storage container.
Put a clean bucket in the middle of the storage container. Have a rock in the bucket to stop it floating around.
Put the lid on the storage container.
Put a rock or small weight on the lid in the middle, so the lid sags above the bucket.

As the sun heats up the container, water will evaporate and condense on the underside of the lid. The water will run towards the centre and drip into the bucket. When the bucket is full of water, you put it into a holding container and put the bucket back in the storage container with another bucket of tap water.

You get pure water with a pH of 7.0, 0 GH, 0KH and no wasted water, no power used and it's cheap to set up.

Sounds brilliant and bet it works great in Australia but the UK hasn’t seen that orange thing in the sky for quite a while…

 

[AlexT]

Sounds brilliant and bet it works great in Australia but the UK hasn’t seen that orange thing in the sky for quite a while…

That's correct. I do have Seasonal Affective Disorder and 3 unplanned ponds in my back garden thanks to the good ol' British summer. Will reply later to replies @Wills and @Colin_T thanks!

 

[AlexT]

If you wanted to go down a hard water route I would look at the Myanmar/Asian mountain stream tank and stock something like

8 Espei Rasboras or Rummy Nose Rasboras
15 Rasboras
8 Rosy Loaches

Wills, I love the look of the above. From what I am reading on seriously fish, even if I stick with 70% RO that would still leave a pH of above 7, and a GH of 107ppm (6 DH). What do you think about the water parameters with 70% RO, or 50% RO brings my GH to about 160ppm (9 DH) and a pH of 7.3 and my set up would be 76 F max. Would that be okay?

 

[seangee]

pH is not that big a deal as long as it is stable (and somewhere in the range of 6-8). Substantial weekly water changes keep it stable - even when KH is 0. GH is far more important. Each of my 4 tanks has developed its own unique ecology and all have different pH levels. IMO its not worth trying to mess with this and is likely to cause more probems than its worth.

 

[TNG]

Sounds brilliant and bet it works great in Australia but the UK hasn’t seen that orange thing in the sky for quite a while…

Even under the hot sun, how many weeks will it take to get enough water for a 110L tank

 

[Wills]

Wills, I love the look of the above. From what I am reading on seriously fish, even if I stick with 70% RO that would still leave a pH of above 7, and a GH of 107ppm (6 DH). What do you think about the water parameters with 70% RO, or 50% RO brings my GH to about 160ppm (9 DH) and a pH of 7.3 and my set up would be 76 F max. Would that be okay?

For those fish you wouldn’t need RO water as they come from hard water habitats.

One thing you would need to do is deal with the nitrates in your tap water to do this naturally if add some house plants to the surface like peace Lilly’s and Pothos but there are other options too like ferns and bamboo. Takes a few weeks/months for them to get into action but once they get going really make a difference.

Wills

 

[AlexT]

For those fish you wouldn’t need RO water as they come from hard water habitats.

One thing you would need to do is deal with the nitrates in your tap water to do this naturally if add some house plants to the surface like peace Lilly’s and Pothos but there are other options too like ferns and bamboo. Takes a few weeks/months for them to get into action but once they get going really make a difference.

Wills

I'll probably keep either 50/50 or 70/30 RO anyway Wills. Based on my likely parameters above for RO mix, according to my research your recommended fish would still be in a good place. I will still have an alkaline pH and a GH of 6, what do you think?

 

[Wills]

I'll probably keep either 50/50 or 70/30 RO anyway Wills. Based on my likely parameters above for RO mix, according to my research your recommended fish would still be in a good place. I will still have an alkaline pH and a GH of 6, what do you think?

Most of those fish come from lake inle or mountain streams in Myanmar so typically encounter some form of hardness in the water Inle gets up to 18gh in some periods and same for some of the streams so you don’t need to do the RO but some people have kept them in softer water and still done ok. In some other species from harder water habitats you get growth problems for fish like Malawi cichlids and some Central American species but not sure how it would affect such small fish.

The only outlier on this is the Espei Rasboras which come from a broad mix of habitats in the wild but mixing that history and generations of farm breeding in neutral water I reckon on balance they are ok going to fare very well. But that is more of a judgement call than evidence based like the fish from lake inle.

Wills