Comparing tap water and reverse osmosis water: my experience and parameters

[Lexat]

I figured it was about time for a separate thread on this. I'm in North London, UK, and I've got some tap water readings and tank readings to share. All hardness readings are in dH, and my tank is still in the fishless cycling stage - it's a small 110L setup.

In terms of stocking, I'm thinking of getting a young BN pleco, a dozen small Bronze or albino corydoras, a Bolivian Ram, and then some schooling fish - possibly Harlequin rasboras or Black phantom tetras, but I'm open to other options. I've had some great suggestions from @boomer and @willie32, so I might explore other rasbora species. The tank will be heavily planted, with a couple of decent-sized pieces of wood and a sand substrate.

For the schooling fish, I'm still undecided - I'm trying to be flexible. I've had some good ideas, but some of my decisions will depend on what water parameters I can realistically maintain, which is why I'm starting this thread.

Here are my tap water readings:
- Ammonia: 0ppm
- Nitrite: 0-0.25ppm (it's been 0.25ppm for the past few days, but that's not uncommon)
- Nitrate: 30ppm
- pH: 7.5
- KH: 10
- GH: 16

And here are my tank readings, which are currently a mix of 70% RO and 30% tap water:
- pH: 7.4
- KH: 4
- GH: 6

I've got a few questions and thoughts:
- I can get RO water easily, but I'm not sure if I want to go above 70/30 RO/tap. I've never used RO before, and I don't want to overdo it.
- Will it take longer for the pH to come down, or will the buffering from my tap water's high KH stop me from getting closer to a pH of 7.0? The colour charts don't show much difference between my tap water and the current tank readings.
- Maybe I should just stick with what I've got? 70% RO seems fine for the corydoras, BN pleco, and Bolivian Ram, but it might not be ideal for the tetras.
- Is it worth trying to get the pH down further? Would the cost and effort be worth it?
- If I'm only going to keep this 110L tank, should I look into getting a cheap RO unit for home use? I've got no experience with these, but I've heard it's possible to get a temporary setup that can be connected to a tap without any plumbing. Any ideas on the cost?

[willie32]

Considering your hard water and nitrate levels, I think using RO water is a good idea, but I've had mixed experiences with it myself. I've opted for a different approach, focusing on fish that thrive in harder water conditions, such as those from Myanmar, Lake Inle, Asian mountain streams, Central America, and Rift Lakes. I've also incorporated terrestrial house plants into my tanks, allowing them to root in the water and substrate. This has been a simple and effective solution for me.

If you're open to exploring a hard water setup, you might want to consider a Myanmar or Asian mountain stream tank. A potential stocking list could include 3 Red Honey Gourami, 8 Espei or Rummy Nose Rasboras, 15 Galaxy or Emerald Rasboras, 8 Rosy or Inle Loaches, and 5 Amano Shrimp, along with 5 Nerite Snails. You could also look into adding a small group of Stiphodon or Sicydium gobies, but be sure to research their specific water requirements.

On the other hand, if you decide to stick with RO water, your original stocking list looks good. However, I do have a bit of biotope OCD, so I think it would be nice to find a smaller tetra species to complement the Bolivian Ram. If you're buying RO water, it's a good idea to stock up in case of emergencies. And if you're using RO, you might as well aim for the softest water possible to benefit your fish. Home RO units start at around £50, but you'll need to factor in the cost of replacing cartridges, which can be around the same price annually. Installing a home RO unit isn't too complicated, but you'll need a suitable space for it and storage for the water.

[coltin]

A 50/50 split of RO and tap water could work well for the fish you're interested in keeping, resulting in a GH around 14dH, which is suitable for the species you've mentioned.

If you're looking for alternative methods to obtain RO water, I'd like to suggest a DIY approach. Creating a solar still can be a cost-effective and environmentally friendly way to produce pure water.

To make a solar still, start by placing a large, plastic storage container outside in direct sunlight. Fill the container with a bucket of tap water and position a clean bucket in the center, weighing it down with a rock to prevent it from floating.

Next, cover the container with its lid, placing a rock or small weight in the middle to create a slight sag. As the sun heats the container, water will evaporate and condense on the underside of the lid. This water will then run towards the center and drip into the bucket.

Once the bucket is full, transfer the water to a holding container and repeat the process with a new bucket of tap water. This method produces pure water with a pH of 7.0, 0dH GH, and 0dH KH, without generating any waste water or using electricity.

[willie32]

A 50/50 split of RO and tap water could work well for the fish you're interested in keeping, resulting in a GH around 14dH, which is suitable for the species you've mentioned.

If you're looking for alternative methods to obtain RO water, I'd like to suggest a DIY approach. Creating a solar still can be a cost-effective and environmentally friendly way to produce pure water.

To make a solar still, start by placing a large, plastic storage container outside in direct sunlight. Fill the container with a bucket of tap water and position a clean bucket in the center, weighing it down with a rock to prevent it from floating.

Next, cover the container with its lid, placing a rock or small weight in the middle to create a slight sag. As the sun heats the container, water will evaporate and condense on the underside of the lid. This water will then run towards the center and drip into the bucket.

Once the bucket is full, transfer the water to a holding container and repeat the process with a new bucket of tap water. This method produces pure water with a pH of 7.0, 0dH GH, and 0dH KH, without generating any waste water or using electricity.

I appreciate the creative idea, but I'm not sure the UK's weather would be too kind to a solar still. We don't exactly get a lot of sunshine here, especially during the winter months.

[Lexat]

Considering your hard water and nitrate levels, I think using RO water is a good idea, but I've had mixed experiences with it myself. I've opted for a different approach, focusing on fish that thrive in harder water conditions, such as those from Myanmar, Lake Inle, Asian mountain streams, Central America, and Rift Lakes. I've also incorporated terrestrial house plants into my tanks, allowing them to root in the water and substrate. This has been a simple and effective solution for me.

If you're open to exploring a hard water setup, you might want to consider a Myanmar or Asian mountain stream tank. A potential stocking list could include 3 Red Honey Gourami, 8 Espei or Rummy Nose Rasboras, 15 Galaxy or Emerald Rasboras, 8 Rosy or Inle Loaches, and 5 Amano Shrimp, along with 5 Nerite Snails. You could also look into adding a small group of Stiphodon or Sicydium gobies, but be sure to research their specific water requirements.

On the other hand, if you decide to stick with RO water, your original stocking list looks good. However, I do have a bit of biotope OCD, so I think it would be nice to find a smaller tetra species to complement the Bolivian Ram. If you're buying RO water, it's a good idea to stock up in case of emergencies. And if you're using RO, you might as well aim for the softest water possible to benefit your fish. Home RO units start at around £50, but you'll need to factor in the cost of replacing cartridges, which can be around the same price annually. Installing a home RO unit isn't too complicated, but you'll need a suitable space for it and storage for the water.

That's correct, the British weather has been quite something lately. I've been dealing with Seasonal Affective Disorder, and to make matters worse, I've got three unplanned ponds in my garden now. I'll get back to you both later, thanks for the input @willie32 and @coltin.

[Lexat]

Considering your hard water and nitrate levels, I think using RO water is a good idea, but I've had mixed experiences with it myself. I've opted for a different approach, focusing on fish that thrive in harder water conditions, such as those from Myanmar, Lake Inle, Asian mountain streams, Central America, and Rift Lakes. I've also incorporated terrestrial house plants into my tanks, allowing them to root in the water and substrate. This has been a simple and effective solution for me.

If you're open to exploring a hard water setup, you might want to consider a Myanmar or Asian mountain stream tank. A potential stocking list could include 3 Red Honey Gourami, 8 Espei or Rummy Nose Rasboras, 15 Galaxy or Emerald Rasboras, 8 Rosy or Inle Loaches, and 5 Amano Shrimp, along with 5 Nerite Snails. You could also look into adding a small group of Stiphodon or Sicydium gobies, but be sure to research their specific water requirements.

On the other hand, if you decide to stick with RO water, your original stocking list looks good. However, I do have a bit of biotope OCD, so I think it would be nice to find a smaller tetra species to complement the Bolivian Ram. If you're buying RO water, it's a good idea to stock up in case of emergencies. And if you're using RO, you might as well aim for the softest water possible to benefit your fish. Home RO units start at around £50, but you'll need to factor in the cost of replacing cartridges, which can be around the same price annually. Installing a home RO unit isn't too complicated, but you'll need a suitable space for it and storage for the water.

willie32, I love the look of the above. Sticking with 70% RO, I'm still looking at a pH above 7, and a GH of 107ppm, or 6 dH. What are your thoughts on that? If I went back to 50% RO, my GH would be around 160ppm, or 9 dH, and my pH would be 7.3. With a max temperature of 76 F, would that work for my setup?

[angelica]

I've found pH isn't a huge concern as long as it's stable - within a reasonable range of 6-8. Weekly water changes keep it in check, even with zero KH. GH, on the other hand, is more crucial. Each of my four tanks has developed its own unique ecosystem, with varying pH levels. I'm of the opinion that tampering with pH can cause more issues than it's worth, and I'd rather not risk it.

[Tigger]

Considering your hard water and nitrate levels, I think using RO water is a good idea, but I've had mixed experiences with it myself. I've opted for a different approach, focusing on fish that thrive in harder water conditions, such as those from Myanmar, Lake Inle, Asian mountain streams, Central America, and Rift Lakes. I've also incorporated terrestrial house plants into my tanks, allowing them to root in the water and substrate. This has been a simple and effective solution for me.

If you're open to exploring a hard water setup, you might want to consider a Myanmar or Asian mountain stream tank. A potential stocking list could include 3 Red Honey Gourami, 8 Espei or Rummy Nose Rasboras, 15 Galaxy or Emerald Rasboras, 8 Rosy or Inle Loaches, and 5 Amano Shrimp, along with 5 Nerite Snails. You could also look into adding a small group of Stiphodon or Sicydium gobies, but be sure to research their specific water requirements.

On the other hand, if you decide to stick with RO water, your original stocking list looks good. However, I do have a bit of biotope OCD, so I think it would be nice to find a smaller tetra species to complement the Bolivian Ram. If you're buying RO water, it's a good idea to stock up in case of emergencies. And if you're using RO, you might as well aim for the softest water possible to benefit your fish. Home RO units start at around £50, but you'll need to factor in the cost of replacing cartridges, which can be around the same price annually. Installing a home RO unit isn't too complicated, but you'll need a suitable space for it and storage for the water.

I'm not sure about the solar still idea, coltin, even if the sun was shining brightly, which it rarely does here. How long would it take to collect enough water for a 110L tank, I wonder.

[willie32]

I figured it was about time for a separate thread on this. I'm in North London, UK, and I've got some tap water readings and tank readings to share. All hardness readings are in dH, and my tank is still in the fishless cycling stage - it's a small 110L setup.

In terms of stocking, I'm thinking of getting a young BN pleco, a dozen small Bronze or albino corydoras, a Bolivian Ram, and then some schooling fish - possibly Harlequin rasboras or Black phantom tetras, but I'm open to other options. I've had some great suggestions from @boomer and @willie32, so I might explore other rasbora species. The tank will be heavily planted, with a couple of decent-sized pieces of wood and a sand substrate.

For the schooling fish, I'm still undecided - I'm trying to be flexible. I've had some good ideas, but some of my decisions will depend on what water parameters I can realistically maintain, which is why I'm starting this thread.

Here are my tap water readings:
- Ammonia: 0ppm
- Nitrite: 0-0.25ppm (it's been 0.25ppm for the past few days, but that's not uncommon)
- Nitrate: 30ppm
- pH: 7.5
- KH: 10
- GH: 16

And here are my tank readings, which are currently a mix of 70% RO and 30% tap water:
- pH: 7.4
- KH: 4
- GH: 6

I've got a few questions and thoughts:
- I can get RO water easily, but I'm not sure if I want to go above 70/30 RO/tap. I've never used RO before, and I don't want to overdo it.
- Will it take longer for the pH to come down, or will the buffering from my tap water's high KH stop me from getting closer to a pH of 7.0? The colour charts don't show much difference between my tap water and the current tank readings.
- Maybe I should just stick with what I've got? 70% RO seems fine for the corydoras, BN pleco, and Bolivian Ram, but it might not be ideal for the tetras.
- Is it worth trying to get the pH down further? Would the cost and effort be worth it?
- If I'm only going to keep this 110L tank, should I look into getting a cheap RO unit for home use? I've got no experience with these, but I've heard it's possible to get a temporary setup that can be connected to a tap without any plumbing. Any ideas on the cost?

For those fish, you wouldn't need RO water since they're from hard water habitats.

To deal with the nitrates in your tap water, you could add some terrestrial house plants to the surface of your tank, like peace lilies or pothos – there are other options too, such as ferns and bamboo. It takes a few weeks or months for them to get into action, but once they do, they really make a difference.

[Lexat]

Considering your hard water and nitrate levels, I think using RO water is a good idea, but I've had mixed experiences with it myself. I've opted for a different approach, focusing on fish that thrive in harder water conditions, such as those from Myanmar, Lake Inle, Asian mountain streams, Central America, and Rift Lakes. I've also incorporated terrestrial house plants into my tanks, allowing them to root in the water and substrate. This has been a simple and effective solution for me.

If you're open to exploring a hard water setup, you might want to consider a Myanmar or Asian mountain stream tank. A potential stocking list could include 3 Red Honey Gourami, 8 Espei or Rummy Nose Rasboras, 15 Galaxy or Emerald Rasboras, 8 Rosy or Inle Loaches, and 5 Amano Shrimp, along with 5 Nerite Snails. You could also look into adding a small group of Stiphodon or Sicydium gobies, but be sure to research their specific water requirements.

On the other hand, if you decide to stick with RO water, your original stocking list looks good. However, I do have a bit of biotope OCD, so I think it would be nice to find a smaller tetra species to complement the Bolivian Ram. If you're buying RO water, it's a good idea to stock up in case of emergencies. And if you're using RO, you might as well aim for the softest water possible to benefit your fish. Home RO units start at around £50, but you'll need to factor in the cost of replacing cartridges, which can be around the same price annually. Installing a home RO unit isn't too complicated, but you'll need a suitable space for it and storage for the water.

I'll probably stick with either 50/50 or 70/30 RO anyway willie32. From what I've read, your suggested fish would still be okay with my likely parameters. I'll still have an alkaline pH and a GH of 6 - do you think that's workable?