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20-24dhfrom the tap, RO unit territory?

Garuf

Member
Joined
30 Oct 2007
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Location
Copenhagen
I’ve been chasing my tail with chlorotic growth in my rotala green for what feels like forever.
The last time I tested the tap water for kh it was around 15, hard, but with aquasoil buffering it hovered at around 10-11dh in the tank, adding a “large pinch” of mgso4 to every 20l of water changes had done much to sort things out but it seems to have been a bandage not a cure.

Out of curiosity, I’ve done a kh test today and the cube has a dh of 23, the 55 of 21 and the big tank of 22. I haven’t tested the iwagumi, no rotalas in that tank. From the tap, the kh is 23dh

I suspect the buffering capacity has long since depleted in the cube which is why the kh is so close to tap parameters.

I really aren’t excited about moving to RO, another cost and waste water to deal with, something else to learn, not as convenient etc.
That said. I also would like to bring my dh down to something more reasonable to just make things a touch easier.

So what are my options, fert and co2 juggling hasn’t really gotten me there yet.

I understand that some of the apartment complexes use hydrochloric acid to reduce the hardness. Is that something?

Is an ro unit my only option? If so, what one should I entertain? Bearing in mind I’m a renter so a hard plumbed one isn’t an option.

What are my options/alternatives?

Bringing tank kh down to circa 10kh is my back of the envelope “that’ll do”.

Rainwater collection isn’t an option due to proximity to a railway line, busy road.

Am I clutching at straws and my tap water is actually fine?

Edited because of unit confusion.
 
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adding a “large pinch” of mgso4 to every 20l of water changes had done much to sort things out but it seems to have been a bandage not a cure.
MgSo4 will have 0 effect on dKh. It will however add dGH.
So what are my options, fert and co2 juggling hasn’t really gotten me there yet.
I understand that some of the apartment complexes use hydrochloric acid to reduce the hardness. Is that something?
Is an ro unit my only option? If so, what one should I entertain? Bearing in mind I’m a renter so a hard plumbed one isn’t an option.
Yes acids will reduce dKH but you better know exactly what you are doing or you might regret it sooner rather than later. The only real option is RO to reduce dKH
Am I clutching at straws and my tap water is actually fine?
That depends. If the only problematic plant is your Rotalla, maybe what about switching to another plant? It will cost you less and give you less headaches. If you really insist on growing plants that require water to be soft then you need to find a source of softer water and since rainwater is not an option the next thing is RO.
 
I’ve been chasing my tail with chlorotic growth in my rotala green for what feels like forever.

I take it you've tried different chelates for your micros, particularly iron?

Out of curiosity, I’ve done a kh test today and the cube has a dh of 23, the 55 of 21 and the big tank of 22. I haven’t tested the iwagumi, no rotalas in that tank. From the tap, the kh is 23dh

I suspect the buffering capacity has long since depleted in the cube which is why the kh is so close to tap parameters.

That is very high. At that level of mineralisation, the soil buffering was probably depleted in the first week!

What are my options/alternatives?

You have three options as far as I can tell:

  1. Stick to species that are easier to grow in hard water, or rather get rid of those you find struggle in your hard water in favour of those that don't as @Hanuman suggests.
  2. Get a decent pumped RO unit - most can be adapted with appropriate fittings for permanent or temporary installation (e.g. fitting onto tap and into sinks). You can also set them up with a container, float valve and some solenoids or electronic ball valves to completely automated the filling of the tank, so fresh RO is ready and waiting when you need it without any input from you.
  3. Collect rainwater - I note your comment on the locality and risk of localised pollution, but that could be mitigated by pumping the water though a HMA filter with carbon block filters to remove the nasties before it enters your tank/water change container.
 
MgSo4 will have 0 effect on dKh. It will however add dGH.
I was/ I am adding mgso4 in the belief adjusting the mg/ca ratio would make fe easier/more available.

That depends. If the only problematic plant is your Rotalla, maybe what about switching to another plant?
Rotala is the one that gives me most hassle because it’s most obvious but most plants have never really been 10/10.

I take it you've tried different chelates for your micros, particularly iron?
Not exactly, I find fertilisers and anything chemistry related just doesn’t make sense to me so I took to adding additional fe using aquasabis fe. I also add addition trace in supplement to the tropica specialized I dose.

That is very high. At that level of mineralisation, the soil buffering was probably depleted in the first week!
You know, that’s something I don’t doubt given how yellow the water I get if not using purigen.

Get a decent pumped RO unit - most can be adapted with appropriate fittings for permanent or temporary installation (e.g. fitting onto tap and into sinks). You can also set them up with a container, float valve and some solenoids or electronic ball valves to completely automated the filling of the tank, so fresh RO is ready and waiting when you need it without any input from you.
Alas I have nowhere to put a unit in the kitchen so it needs to be able to be attached to the tap and used then chucked back under the tank. I don’t have the option to store the 60l of RO I’d need to split my water 50/50 so what ever Ro I end up with needs to be able to come straight from unit to tank or via a bucket to the tank.
  1. Collect rainwater - I note your comment on the locality and risk of localised pollution, but that could be mitigated by pumping the water though a HMA filter with carbon block filters to remove the nasties before it enters your tank/water change container.

Also boils down to ability to store and collect - I’m a renter and I have no outdoor space to access.
 
Not exactly, I find fertilisers and anything chemistry related just doesn’t make sense to me so I took to adding additional fe using aquasabis fe. I also add addition trace in supplement to the tropica specialized I dose.
You don't need to be a chemistry buff - just try buying some DTPA Iron or EDDHA Iron, available from eBay or Amazon, and ask o her about mixing up a solution to dose. The potential problem with your current Iron dosing is the high pH could be making the iron unavailable to your plants.

I don’t have the option to store the 60l of RO I’d need to split my water 50/50 so what ever Ro I end up with needs to be able to come straight from unit to tank or via a bucket to the tank.

RO units are only around 95% efficient depending on unit, so at 23dKH from the mains water, you'll end up with around 1-1.5dKH water out of the RO unit - no need to cut with any tap water. If you have shrimp you can add some GH directly to the tank on water change, if you don't have shrimp, then you should be fine as is with the Mg you are adding as part of your ferts, and the Ca that will still be in the RO water produced.
 
Hmm,
I've had a look at it and it seems that RO units aren't what I remember them costing, or at least, there are cheap options I've never registered before—whether they're any good or not? My in the mind budget was 100 Euros and there's half a dozen options. The Dennerle Osmosis professional 190 seems like it'd fit the bill.

I repeated the water test this evening because I was doubting myself, the numbers just felt high, still 23dkh.

I've also had a look at what I'm dosing, I'm using Aqua Rebell Mikro Spezial Eisen and Aqua Rebell Mikro Basic Eisen in addition to Tropica Specialised. I believe these are dtpa chelated?
Given the hard water moving to EI would likely make sense but I've got gallons of ferts to work through yet.

I've posted about this in the past but my memory isn't as good as darrels and I'm blanking on finding the right link.
link found Tropica specialized dosing rules of thumb
 
If you do decide to get one, do yourself a favour and don't buy any RO system from an aquarium brand. They are exactly the same as any regular RO sytem, only 2x more expensive.

How much water would you need to make? Bear in mind that without a booster pump and/or double RO membrane your unit will be both slow and wasteful. If you're commited to using it then investing in at least a booster pump would make it a much more pleasant experience.

For reference I live in the Netherlands (so water is coldish), have 2x 75gpd membranes and a small booster pump. My RO filter makes 0.5l per minute with almost 1:1 clean to waste water ratio.
 
Hard plumping just isn’t an option, so I can’t see a booster pump happening. I’m a renter so what the best option is is likely not an option at all. 🤔
 
Hard plumping just isn’t an option, so I can’t see a booster pump happening. I’m a renter so what the best option is is likely not an option at all. 🤔
220l of tanks, so 110lish of water changed each week. A minimum of 60l of ro if I split the water 50/50 - more the softer the water needs to be.

Seems like RO is a dead end given that I can’t hard plumb and I have no possibility to store water between changes if it’s going to take such a long time.
 
220l of tanks, so 110lish of water changed each week. A minimum of 60l of ro if I split the water 50/50 - more the softer the water needs to be.

Seems like RO is a dead end given that I can’t hard plumb and I have no possibility to store water between changes if it’s going to take such a long time.
I booster can be used just fine even if you are not hard plumbing the RO unit, they fit inline between the incoming mains and the RO membrane.

As said above, RO is going to be the best way to keep your KH down, is there anywhere local you can buy RO water from?
 
There is but they charge enough that I can buy a unit within 4 water changes.


This is the unit I see that a lot of home brewers here use because you don’t need a booster on most systems.
 
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There is but they charge enough that I can buy a unit within 4 water changes.


This is the unit I see that a lot of home brewers here use because you don’t need a booster on most systems.

You would need to test your mains pressure from the tap - if its anything like the UK, I doubt you'll be getting 2.1 bar, let alone the 3bar they recommend for the 12 litre per hour optimum output. I personally would consider a booster pump mandatory.

Even at 3 bar that's over 9 hours to generate the 110 litres you need - and I don't see the point in cutting it 50/50 with tap water, that's a waste of time. The whole point of using an RO unit is to achieve soft water, cutting 50/50 with your tap water, you'll still end up with hard water at 12+dKH.

In terms of a storage containers, you can get these in a wide variety of sizes to help them fit specific spaces. I had to get a vary narrow tank for my system so I could slot it hidden away behind a piece of furniture.

For example this is a 60 litre tank with a very small foot print of 35cm x 25cm:


WDT60TNA5_main_60-litre-tower-water-tank.jpg

or a 75 litre one with narrow footprint, to more easily fit under a desk etc:


WDT75UNA8GH_main_75-litre-upright.jpg
 
Hard plumping just isn’t an option, so I can’t see a booster pump happening. I’m a renter so what the best option is is likely not an option at all. 🤔
I’d personally make sure you go for a RO with booster, stops the worry about water pressure and makes the unit far more productive.

I don’t have my unit hard plumbed in. I use a garden tap adapter and simply connect the unit to my garden tap, plug it into an outdoor socket and away I go. There are various adapters you can use for kitchen taps etc.

I wasn’t very keen on RO initially but it is very strait forward to set up and use. The only issue is waste water.

Cheers
 
I think I have to do a bit more leg work on working out a system.

Unfortunately, the fact remains that I rent a room. Not having the kitchen tap usable for a day at a time won’t fly.
There’s just no option for storing large amounts of ro water without a lot of comprise and or creativity so the ro unit needs to produce enough quickly enough to minimise the impact of its use and then be put back away.

The splitting of the water 50/50 comes down to not necessarily needing (super) soft water, by comparison, for the tank inhabitants so minimising the amount I would need to store is kept to the minimum I can get away with.
 
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