Tap water or Rain water??

maj74

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I ran a Discus tank several years ago, and used only rain water very successfully.

My return to aquascaping won't be discus, but an 80cm high tech planted tank.

I will bring a water feed in from outside to a sump under the tank, so that water can come up to room temp before carrying out water changes.

I can't decide whether to bring in tap water or rainwater? I know rainwater has the advantages of no chlorine etc for livestock, but also know it's lack of hardness can cause issues with CO2 injection and PH crashes.

What are peoples' thoughts on which I should use? do the benefits of one outweigh the negatives?
 
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dw1305

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Hi all,
I've been a rain-water user since the 1970's and I would always prefer it to tap water. I'm <"pretty risk adverse">, and I honestly think <"it is a safer option">.
I know rainwater has the advantages of no chlorine etc for livestock, but also know it's lack of hardness can cause issues with CO2 injection and PH crashes.
You can re-mineralise rain-water like you would RO water. Rain water tends to be <"more variable during the year">, so rather than adding a set amount of dGH/dKH I use a <"conductivity meter to give me a datum range"> where plant growth is acceptable. I don't add a specific mix to raise hardness, we have a hard tap supply (about 18dKh/dGH and ~all from Ca++ and 2HCO3- ions), so I just mix in some tap if the values falls below about 80 microS (50 ppm TDS).

I'm not a CO2 user, but most of what you read about <"pH crashes and pH stability is wrong">, there is a more complete explanation in the linked thread, <"Is there a need to......">. <"Chemical buffering is quite a complex area">, and my personal opinion is that some unscrupulous companies have exploited this to <"sell worthless products">.

When you add CO2 you change the <"equilibrium point of the carbonate ~ CO2 buffered system, and the pH falls">.

cheers Darrel
 
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Conort2

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I have started using rainwater following @dw1305 recommendation as I now keep soft water species that need low tds water. I can’t say I’ve had any issues and I am still using co2. Plant growth is better than it was I believe my hard water affected nutrient uptake. I have also switched to a lean dosing method following the change as I don’t think my species would appreciate the high tds associated with ei dosing and the plants are still growing great.

I have no idea what my ph is and Do not worry about it, my fish are from soft water/ black water areas so I know they can deal with a really low ph. I rely on my tds to tell me if my water I suitable for my fish and try and keep it under 100ppm. Think my rainwater has a tds of around 40/50 but time ferts and what no are added it goes up some what.

cheers

Conor
 

Oldguy

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I cant decide whether to bring in tap water or rainwater?
Why not mix the two together to get the hardness you want. I go for a very soft mix and then increase hardness with magnum sulphate (Mg is a macro nutrient and is often lacking in UK tap water)

Some tap waters have a high pH which is not related to hardness but is a result of water treatment. This can put a demand on injected CO2.

Very hard water can interfere with chelated trace & micro nutrients by GpII competition, but this can be overcome by using a more stable chelating agent. There are lots of threads on this subject in this forum.

Measurement of both pH and Total Dissolved Solids (TDS) is problematic with very soft waters.

Chemicals in solution are there as independent ions and are not there as the compounds that were put in ie MgSO4 and KNO3 are there as Mg++ ions K+ ions
SO4- - ions and NO3- ions. Think of it as a super swingers party.

Most plants appear not to be hardness sensitive with a few that are.

With the Estimated Index (EI) approach are nutrients are in excess it is a matter of balancing light and carbon dioxide (often a circulation issue). For many the lights are too bright and on for too long.

Start with lots of fast growing plants and thin out and replace once the tank as settled down.

Allelopathy between higher plants and algae is an issue that needs exploring. Good planted tanks have no algae issues, those with poor plant growth have algae issues. Allelopathy may be contentious but is worth considering.


Good luck with your endeavors.
 

hypnogogia

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Yup, second rain water cut with tap to get the first hardness. Where I am I also need to be careful of phosphate sin the top water, so the amount off tap I add depends on the time of year. We have lower phosphates in winter.
 

maj74

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Can it, is that from personal experience or info from another source?

Not from personal experience - never had a problem with my Discus tank, but then it wasn't heavily planted with lots of CO2

I may have remembered incorrectly, but I thought a lack of hardness meant low buffering capacity and risk of pH changes.

Why not mix the two together to get the hardness you want. I go for a very soft mix and then increase hardness with magnum sulphate (Mg is a macro nutrient and is often lacking in UK tap water)

Some tap waters have a high pH which is not related to hardness but is a result of water treatment. This can put a demand on injected CO2.

Very hard water can interfere with chelated trace & micro nutrients by GpII competition, but this can be overcome by using a more stable chelating agent. There are lots of threads on this subject in this forum.

Measurement of both pH and Total Dissolved Solids (TDS) is problematic with very soft waters.

Chemicals in solution are there as independent ions and are not there as the compounds that were put in ie MgSO4 and KNO3 are there as Mg++ ions K+ ions
SO4- - ions and NO3- ions. Think of it as a super swingers party.

Most plants appear not to be hardness sensitive with a few that are.

With the Estimated Index (EI) approach are nutrients are in excess it is a matter of balancing light and carbon dioxide (often a circulation issue). For many the lights are too bright and on for too long.

Start with lots of fast growing plants and thin out and replace once the tank as settled down.

Allelopathy between higher plants and algae is an issue that needs exploring. Good planted tanks have no algae issues, those with poor plant growth have algae issues. Allelopathy may be contentious but is worth considering.


Good luck with your endeavors.


I would prefer from a simplicity point of view, to use one or the other. I don't want to be bringing more hose feeds in from outside than I need to. I can connect the pipe into the house to either a water butt or the tap. Yes it would be technically feasible to switch between the two - but I am trying to keep the system as simple and hassle free as possible.

Why not mix the two together to get the hardness you want. I go for a very soft mix and then increase hardness with magnum sulphate (Mg is a macro nutrient and is often lacking in UK tap water)

Some tap waters have a high pH which is not related to hardness but is a result of water treatment. This can put a demand on injected CO2.

Very hard water can interfere with chelated trace & micro nutrients by GpII competition, but this can be overcome by using a more stable chelating agent. There are lots of threads on this subject in this forum.

Measurement of both pH and Total Dissolved Solids (TDS) is problematic with very soft waters.

Chemicals in solution are there as independent ions and are not there as the compounds that were put in ie MgSO4 and KNO3 are there as Mg++ ions K+ ions
SO4- - ions and NO3- ions. Think of it as a super swingers party.

Most plants appear not to be hardness sensitive with a few that are.

With the Estimated Index (EI) approach are nutrients are in excess it is a matter of balancing light and carbon dioxide (often a circulation issue). For many the lights are too bright and on for too long.

Start with lots of fast growing plants and thin out and replace once the tank as settled down.

Allelopathy between higher plants and algae is an issue that needs exploring. Good planted tanks have no algae issues, those with poor plant growth have algae issues. Allelopathy may be contentious but is worth considering.


Good luck with your endeavors.

Here in Suffolk we have typically very hard water.
 

dw1305

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Hi all,
I may have remembered incorrectly, but I thought a lack of hardness meant low buffering capacity and risk of pH changes
It does, but pH is never stable in soft water and that it isn't a problem for fish etc unless you keep Lake Tanganyika Cichlids etc.
Here in Suffolk we have typically very hard water.
I would go with rain-water. You won't need very much tap water to give you some dGH/dKH, it is going to be a couple of litres at most, so <"wouldn't need plumbing in">. An issue might be <"lack of rain">?

@MirandaB is in <"your part of the world"> and she uses tap water and may be able to advise you on plants etc. if you wish to go down that route.

cheers Darrel
 

Conort2

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I would prefer from a simplicity point of view, to use one or the other. I don't want to be bringing more hose feeds in from outside than I need to. I can connect the pipe into the house to either a water butt or the tap. Yes it would be technically feasible to switch between the two - but I am trying to keep the system as simple and hassle free as possible.
Just go for rainwater then, I don’t bother cutting mine with anything. In the summer it’s a case of pumping directly from the water butt outside into the aquarium however now the temperature has dropped it’s pumped into a bin indoors first and preheated.

will you be going for domestic discus or wilds?

Cheers

Conor
 

dw1305

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Hi all,
will you be going for domestic discus or wilds?
I ran a Discus tank several years ago, and used only rain water very successfully. My return to aquascaping won't be discus, but an 80cm high tech planted tank.
I think the OP used to keep Discus in rain-water, but is now going to have a planted tank with other fish.

cheers Darrel
 

maj74

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Just go for rainwater then, I don’t bother cutting mine with anything. In the summer it’s a case of pumping directly from the water butt outside into the aquarium however now the temperature has dropped it’s pumped into a bin indoors first and preheated.

will you be going for domestic discus or wilds?

Cheers

Conor

It's not even discus. Just a high tech planted tank with Tetras of some sort. Its only 140-150 litres in total. I'm just putting lots of time and design into a piped / pumped setup, allowing semi automatic water changes, to keep maintenance time demands to a minimum.
 

Tim Harrison

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I'd use rainwater too, but depending on how much storage capacity you have you might find yourself having to switch to tap or RO water during dry spells.
 

maj74

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I'd use rainwater too, but depending on how much storage capacity you have you might find yourself having to switch to tap or RO water during dry spells.

That is a good point. We can be as dry as the UK gets over here....

However - The water butt and outside tap are next to each other - so switching the feed hose (to the storage sump under the tank) over wouldn't be a huge issue on the occasions in summer it proved necessary. Want to get away from having 25L water carriers sitting in the living room. - WAF and all that.
 

Conort2

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It's not even discus. Just a high tech planted tank with Tetras of some sort. Its only 140-150 litres in total. I'm just putting lots of time and design into a piped / pumped setup, allowing semi automatic water changes, to keep maintenance time demands to a minimum.
Apologies You did say in your initial post.

you’ll only be using roughly 70l a week so a couple of water butts linked together should last you a while. If you’re cutting with tap it should last even longer. You mention pumping directly from the butt, will you be be preheating the water somehow before?


cheers
 

MirandaB

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Hi all, It does, but pH is never stable in soft water and that it isn't a problem for fish etc unless you keep Lake Tanganyika Cichlids etc. I would go with rain-water. You won't need very much tap water to give you some dGH/dKH, it is going to be a couple of litres at most, so <"wouldn't need plumbing in">. An issue might be <"lack of rain">?

@MirandaB is in <"your part of the world"> and she uses tap water and may be able to advise you on plants etc. if you wish to go down that route.

cheers Darrel
Yes I'm on the border but for most of my fish I've had to go RO/Tap mix now when there isn't enough rainwater to do a mix.
I used to use straight tap and it certainly wasn't an issue to growing plants although if using injected co2 it does mean you tend to use more co2 and of course the inevitable limescale build up is a pain.
 

maj74

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Apologies You did say in your initial post.

you’ll only be using roughly 70l a week so a couple of water butts linked together should last you a while. If you’re cutting with tap it should last even longer. You mention pumping directly from the butt, will you be be preheating the water somehow before?


cheers

It’s pumped into a sump in the cabinet so it can come up to room temperature.
 

rubadudbdub

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I'd use rainwater too, but depending on how much storage capacity you have you might find yourself having to switch to tap or RO water during dry spells.

I've not used them myself as I have started mixing rain water with tap, but Spotless water could be an easy RO back up without forking our for an RO unit you won't use for long periods. The website says Bury St Edmunds or Ipswich when I type Suffolk into the location search.

https://www.spotlesswater.co.uk/Loc...DRk_-eQOSI4qlWSstH8A4gHvpovA2nYxoCLA8QAvD_BwE
 

tam

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Timely question, I'm just thinking of swapping from RO+remineraliser to rain+very hard tap. Checked the new water butt and it has a TDS of 25. Might need to flush it through a bit though as it is an ex whisky barrel :D ... and it needs a tap adding.

We used to use rain when I was a kid and had great plant growth, but that was all low tech stuff.
 

dw1305

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Hi all,
Checked the new water butt and it has a TDS of 25. Might need to flush it through a bit though as it is an ex whisky barrel :D ... and it needs a tap adding.
I think that should be fine.

It doesn't have many salts (ions) present because of the low TDS. If alcohol was still seeping out of the wood, it wouldn't show as TDS (it isn't an ion), but it would be less dense than water, so it would form a surface layer, which would continually evaporate.

cheers Darrel
 
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