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Question about low tapwater kh, possible calcium deficiency.

4923 Views 17 Replies 6 Participants Last post by  waterspider, 
W
So I'm making reasonably good progress with my 65ltr planted "learner tank" - thanks for the help so far (most of which has been just from reading other's posts) I've got my head around lighting (this is low light/low tech, no C02 ... yet), water flow, basics of ferts, and plants are growing fine but not yet thriving, but I've at least got my algae issue under control, and I've just started adding fish (3 male guppies from my other 120ltr non- planted tank, and two amano shrimp).

I'm in the process of getting to know more about my water parameters, and while learning about working with my low tapwater KH, keep coming across posts/articles that suggest I might have a calcium deficiency effecting both fish and plants in both tanks.

My question is about ways to add calcium that might serve simultaneously to nudge up my KH for buffering, act as a micro supplement for plants and fish, and ensure my shrimp have enough for their shells. Calcium carbonate as crushed coral seems to be the most popular suggestion for buffering purposes (other than bicarbonate soda, obvsly), but I can't figure out where to put them. My substrate is in and planted, and I don't have chambers in my filter (in fact it's already got a bunch of ceramic rings from my 120gal wedged in there to support cycling) I saw a post suggesting pharmaceutical calcium carbonate, but my local pharmacist tells me all their products have additional ingredients, which feels a bit wild card for me. Which leaves crushed limestone, or limewater, research for which is sending me into the world of marine aquariums, which are a bit over my head. I am struggling to find anything on ingredients in commercial buffering and marine compounds. All I've learned so far, really, is that there are good reasons for why one should be cautious about adding any chemical to your tank!

Anyone got ideas for a good starting point to learn more about adding calcium and calcium carbonate in freshwater tanks?

My water comes out of the tap at ph 7.5, GH 3, KH 0. My non planted 120ltr is currently ph 7, kh 1, gh 4.5. My planted 65ltr is ph 7, kh 3, gh 4. The higher GH/PH are due to some experiments with buffering I was trying out last week, which have not yet fully dissipated from water changes. Not entirely sure what's boosted it in my 120ltr, though it is just clearing a salt treatment with some eSHa minerol added.

Calcium concerns are leaf curl on new growth of my ludwiga repens in the planted tank, and some issues with rickets in my guppies in my 120ltr. I'd previously assumed this was down to genetics, and was culling fry as soon as I saw it in them, but one site suggested it could also be deficiency in vit d, calcium or potassium. The shrimp are fine so far, but then I've only had them a week.

I alternate King British flakes and Hikari guppy pellets, with blanched peas once a week, for the fish. Shrimp have also been getting some Hikari shrimp pellets to supplement their algae munching. I've been using Tropica Premium (micro ferts) for the plants for now - until I can get a better understanding of mixing dry frets. It's not ideal - I'd planned to add fish sooner for macros, but then noticed some health concerns I thought might be parasites- hence them getting a salt treatment in the bigger tank.

Sorry if this is long. And thanks in advance for your help!
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S
This was very long. Add CaCl2 to raise your gH. I would also add some MgSO4. In a ratio of 3:1. Then add baking soda if you want to raise your kH. Your plants aren't thriving because of CO2. I would highly recommend you try DIY co2 to see if it makes a difference before dumping a bunch of chemicals to your tank. Your gH and kH looks good. Maybe raise the gH a little bit.

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W
scx said:
This was very long. Add CaCl2 to raise your gH. I would also add some MgSO4. In a ratio of 3:1. Then add baking soda if you want to raise your kH. Your plants aren't thriving because of CO2. I would highly recommend you try DIY co2 to see if it makes a difference before dumping a bunch of chemicals to your tank. Your gH and kH looks good. Maybe raise the gH a little bit.

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Thank you - bit of googling later. So Epsom Salts are MgSO4. Right? I don't know where I'd find CaC12. Not looked into salts/dry ferts at all yet, so this is a bit over my head. Maybe I should wait till I've started researching this before asking. It's next on my list after learning about acidity, alkalinity etc - which I'm still wrestling with a bit.

I had problems first time round with DIY C02. Algae - well diatoms - wiped out my plants - though it's not clear that was the cause. But it did trigger a significant and fast ph crash that preceeded the explosion. I'm calling this my learner tank because I'm using it primarily to get my head round these things more systematically this time.

But I'll take not of what you say to help me on my quest for the "why" answers at any rate.:)
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Zapins
Any photos of your plants? It may not be a Calcium deficiency. A GH of 3 is fairly low but unless it is 100% MgSO4 I would assume you have enough calcium to get by.

waterspider said:
So Epsom Salts are MgSO4. Right? I don't know where I'd find CaC12. Not looked into salts/dry ferts at all yet, so this is a bit over my head. Maybe I should wait till I've started researching this before asking. It's next on my list after learning about acidity, alkalinity etc - which I'm still wrestling with a bit.
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Yes MgSO4 is epsom salt. You can buy all the ferts you need from here: http://www.aquariumfertilizer.com/index.asp?Option1=cats&Edit=2&EditU=1&Regit=2

Alkalinity, and pH aren't super important for freshwater systems. GH is a little more important, but the NO3, PO4 and micro nutrients are much more important along with good lighting and an appropriate temperature. Freshwater species are well adapted to changes in pH and alkalinity because they come from ponds, streams and rivers where every time it rains those parameters fluctuate wildly compared with marine fish where those conditions almost never change.
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W
http://www.advancedaquarist.com/2003/2/chemistry

It's actually this article I'm trying to follow.

I'm gong to sound like a proper ingratiate towards everyone being so kind with their time here, but I really was just hoping someone could link me to something "intermediate amateur" level on supplementing calcium and calcium carbonate in freshwater tanks. I get the impression it's an uncommon issue - more people on forums seem to have hard tap water. (I also get the impression I'm lucky, overall, to have neutral water,given how much time and effort some spend on RO and what have you)

I'm not massively concerned about my plants overall just yet (or my fish for that matter - they've been reasonably fine for 3 yrs now after all - barring occasional problems from overbreeding/stocking levels). The plants have been in three weeks. I have new growth and no major die off. Some plants are doing better than others for sure, but my fast plants are doing fine. My priority right now is to add fish. Once they've settled in,I will be gauging C02, ferts, and deciding *if* I want to muck around with buffers and salts.

My KH in the planted tank is pretty much 100% bicarbonate soda - as that's what I used last week to buffer it. I still have my 4DKH drop checker in there from my first C02 attempt, and it's ph reading against the tank water is pretty much identical.

Woah! Zapins - that would be a great site if I were in the US (I'm in the UK) - but $26 shipping for $3 of calcium chloride is a bit rich for me. :)

I'll go see if I can find a UK equivalent though.
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D
GH is General Hardness, the measure of Ca and Mg. This is not a buffer for pH.

KH is Carbonate Hardness. This is the buffer for pH.

To raise the GH look into products that may be called GH booster. If Seachem is available on your side of the pond look for Equilibrium.
These will have both Ca and Mg, usually in something close to the right balance for the plants and fish. I have heard of some GH boosters that also have sodium chloride (salt). Not good.

To raise the KH you can use baking soda (also called bicarbonate of soda) it is sodium bicarbonate. (I think cooking in the UK uses a slightly different product, but maybe it is the same.)
Potassium bicarbonate is another good material. Here, it is available in certain grocery stores and health food stores. This would raise the KH without adding sodium to the tank, which some people try to avoid.
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W
http://reefkeeping.com/issues/2006-02/rhf/index.php

Just parking this here to read later following though on the calcium chloride/Epsom salts point - still in marine aquarium territory, interestingly.

Gah! Where's the Skeptical Aquarium article on this when you need it. I find his "pitch" just right for my past beginner but long ways from master level of knowledge.

Thanks, Diane. Baking soda is the same in US and UK. Baking *powder* is also commonly sold, which is bicarbonate soda mixed with an acid (cream of tartar) - I know this from baking. Like I said, it's calcium I'm interested in finding out about right now.
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H
You say you have zero KH, which is not good. I doubt that you actually do have zero KH, but you may have less than one degree of KH. KH does not buffer the pH, it raises it. Fish and plants generally come from waters with a KH above zero, and while it does fluctuate when it rains, I doubt that it ever goes to zero. If you add calcium carbonate you are adding to the GH (the calcium) and to the KH (the carbonate). There are many crystal forms of calcium carbonate, but they all add to the GH and KH as they dissolve into the water, usually very slowly. Coral is one form to use, which dissolves very slowly. Chalk is another form.
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plantbrain
Plant issues are much more likely a CO2 issue, I've never seen a Ca++ related issue, unless you use a salt exchange water softener, or use pure RO, which you are not.........

It is virtually impossible to have a Ca++ deficiency.
Often blamed for a great many things but CO2, not Ca++ is the root of most evils and poor plant health, growth etc, roughly 95% of so called fertilizer issues.
Certainly the most lethal thing for fish when used incorrectly.

Focus there. UKAPS.org is a good, well, the best site for folks in the UK for fert supplies.
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W
Well, I was testing kh in 10ml tapwater, and it changes on first drop. Tried it this morning in 20ml and it changed on 2nd drop. So I'm looking at tap water kh of 0.25 dKH.

If I'm just prioritizing buffering, I'm fine working with bicarbonate soda. Like I said in the OP, I've nowhere physically I can put crushed shells. Or find real chalk for that matter. It was just the rickets issue combined with the leaf curl that got me thinking about calcium.

I was running DIY CO2 briefly last week,mainly to pay more attention to ph stability this time, so it's easy enough to get it going again. Is buffering going to be more crucial with C02?

Just parking this article here (hope you guys don't mind - it's just useful to keep things clustered) - it's emphasising KH/GH for fish health rather than just buffering.http://www.americanaquariumproducts.com/aquariumkh.html

Seachem equilibrium info - so it is just trace minerals, no buffers? (http://www.seachem.com/Products/product_pages/Equilibrium.html
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H
Again, KH does not buffer the water against pH changes due to CO2. "Buffer" means to keep the pH changes very low, over a range of added low or high pH compounds. KH won't do that for CO2 changes. All KH does is raise the pH for a given ppm of CO2 in the water. It isn't a good idea to add real buffers to the tank water, but if you did you would use a mix of something like Seachem acid buffer and Seachem alkaline buffer. The pH that it would buffer to depends on the ratio of the two buffers, to a not at all simple to determine value.
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W
I think I'm muddling my questions and understanding of replies. The C02 option is still throwing me. I'll try and break them down. Thank you for being patient with me!

Q 1) Do I need to add minerals to soft water for plant health? Answer a). No, add C02 instead, b) no, add c02, but could consider a home mix solut of calcium carbonate and Epsom salts, possibly with sodium bicarbonate as a buffer. C) consider seachem equilibrium for added minerals.

On the basis that most said no/not necessary to minerals, I started off my DIY C02 again yesterday, and after 4hrs my pH had dropped a point. 3hrs later it was down another 1/2 point. This was making me nervous, as it was heading under 6 - and that was before lights out. I didn't want to wake up to dead fish, so I disconnected it. Decided I'm finding DIY to hard for now and that I'd get some liquid carbon today instead.

Q2. Should I buffer soft water anyway? I *am* finding it hard to follow subtlety different uses of the term KH in accounts of buffering. It seems to be used variously and interchangeably to mean "bufferring capacity", "alkalinity" and "mineralization" depending on which chemical reactions collectively registered bythe KH reading. For a newbie to the topic I can't distinguish usage.

I also struggle to understand why people on planted tank forums say "don't worry about pH drops with C02 - the fish will be fine", when I'm concerned with my already neutral pH dropping low enough to disable my nitrifying bacteria. Not sure my plants are stable enough yet to depend on for filtration. I've already had one pH crash adding C02.

This morning my tank is thick with diatoms again! I'd only just got them under control, having had them wipe out my tank first time round (using blackout, New lights, increased flow through the tank, and amano shrimp) I don't want to jump to conclusions, but that's the 2nd time this has happened from adding DIY/fast drop in pH.
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D
Here is how I do this:

1) Set the GH to what the fish want. Soft water fish: 3-5 degrees. Most community tank fish GH up to 9 degrees. Hard water fish over 10 degrees. Do this with a balanced product (commercial or DIY) that has something more or less about 4 parts Ca: 1 part Mg.

2) Make the KH pretty close to the GH. For soft water fish, that will be low enough that the KH won't do much for the pH. The pH will be controlled by other things (such as CO2, peat moss, organic processes such as decomposition)
For hard water fish a high KH will also keep the pH higher.

3) If you have black water species add some peat moss to add the organic acids these fish like.

I have the skeptical aquarist bookmarked. Here is the beginning of the Water articles, there are quite a few!

http://www.skepticalaquarist.com/water

Carbonate is a buffer that can stabilize the pH in aqueous solutions.
http://en.wikipedia.org/wiki/Buffer_solution

In aquariums:
KH under 3 degrees offers little (but not zero) buffering. In my tanks the pH will be down to about 6 or lower when the KH shows 0 degrees. The pH will climb to the low 6s when the KH is 2 degrees.
KH from about 3-5 offers some buffering, often considered just about right when you are adding CO2. The pH may change, but within the range of most soft water fish.
KH over that usually buffers the pH into the alkaline range, well over 7, and into the 8s when the KH is into double digits. This is good for many live bearers, Rift Lake Cichlids and some Rainbow fish. It does make the pH hard to change (part of the definition of buffer) when the KH is this high.
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W
I love the Skeptical Aquarist, Diana - it's been my go-to site for most things, and I had read a few of the water articles. You prompted me to 're-read them all in order, and I *think* I'm starting to get it!

So ... using his accounts - an hypothesis for why adding C02 to my tank seems to be triggering diatoms (and other algae - but diatoms lead the parade) Adding C02 to my soft, pH neutral water acidified it further - dropping from pH 7 to 5.5 in a few hours. This knocked out my nitrifying bacteria, prompting an ammonia spike. As the water was acidic, the ammonia converted to ammonium, which is why there was no fish distress/symptoms. I don't have enough plants to avail of the ammonium, so diatoms jumped in to gobble it up.

Conclusion: I should not add C02 unless I plan to add a buffer to counteract swings, because (contrary to most advice on algae control) it will have an unintended consequence of increasing algae.

Does this sound possible to you guys? Have any of you run softwater aquariums with C02? Anyone in the tank journals doing so who I could follow?

Thing is, first time this happened, I was for a HC Cuba carpet, as most say it is really needs it. Diatoms nearly wiped out all my plants that time, but having seen it used a "foliage" on aquatic "bonsai trees", I'd tied the few survivors to the highest point of my wood - and it's been doing pretty well up there.

Let's hope it can survive this second outbreak!
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H
Diana said:
.......
Carbonate is a buffer that can stabilize the pH in aqueous solutions.
http://en.wikipedia.org/wiki/Buffer_solution

.......
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Diana, that reference does not say that carbonate is a buffer. Instead, it says, correctly, that a mix of carbonic acid and carbonates will buffer an aqueous solution against addition of strong acids or bases. CO2 is not an acid or base, let alone a strong one. When we add carbonate to water that has CO2 in it (almost all water) we get a mix of carbonic acid and carbonate. That mix does buffer against adding small amounts of acids or bases, but not CO2. The only effect of the carbonate addition on pH is to raise it.

Our hobby is infused with lots of myths, and carbonate as a buffer against pH changes due to CO2 is one of them.
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W
Hurrah! My hypothesis seemed to be right - water change, plant wash and replanting the most affected plants, and adding nutrient greedy guts (water lettuce and spring growth willow sticks) worked. Tank is clean as a whistle today.

Now I can get back to the bufferring decision. I've found UK suppliers for all DIY and commercial suggestions. Will look into it a bit further - but might make do with slow, steady growth while I think on it. It's only really the repens that's looking a little crinkly.

Thanks for all the input, guys!
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H
waterspider said:
I love the Skeptical Aquarist, Diana - it's been my go-to site for most things, and I had read a few of the water articles. You prompted me to 're-read them all in order, and I *think* I'm starting to get it!

So ... using his accounts - an hypothesis for why adding C02 to my tank seems to be triggering diatoms (and other algae - but diatoms lead the parade) Adding C02 to my soft, pH neutral water acidified it further - dropping from pH 7 to 5.5 in a few hours. This knocked out my nitrifying bacteria, prompting an ammonia spike. As the water was acidic, the ammonia converted to ammonium, which is why there was no fish distress/symptoms. I don't have enough plants to avail of the ammonium, so diatoms jumped in to gobble it up.

Conclusion: I should not add C02 unless I plan to add a buffer to counteract swings, because (contrary to most advice on algae control) it will have an unintended consequence of increasing algae.

Does this sound possible to you guys? Have any of you run softwater aquariums with C02? Anyone in the tank journals doing so who I could follow?

Thing is, first time this happened, I was for a HC Cuba carpet, as most say it is really needs it. Diatoms nearly wiped out all my plants that time, but having seen it used a "foliage" on aquatic "bonsai trees", I'd tied the few survivors to the highest point of my wood - and it's been doing pretty well up there.

Let's hope it can survive this second outbreak!
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If you have a KH above 1 dKH, or maybe 2 dKH, you should be able to add CO2 without any concern about the pH. Too many people do that and don't have big algae problems. When you start adding stuff to raise the water's KH, you add another complexity to doing water changes. You will then want to add that "stuff" to the change water before putting that change water in the tank. I wouldn't worry about doing that for a 1 dKH difference in KH between the change water and the tank water, but for a 4 dKH change I would be concerned about how the sudden changes in KH affect the fish. The best problems to solve are problems you actually have, not problems you are assuming you might run into.
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Hoppy said:
If you have a KH above 1 dKH, or maybe 2 dKH, you should be able to add CO2 without any concern about the pH. Too many people do that and don't have big algae problems. When you start adding stuff to raise the water's KH, you add another complexity to doing water changes. You will then want to add that "stuff" to the change water before putting that change water in the tank. I wouldn't worry about doing that for a 1 dKH difference in KH between the change water and the tank water, but for a 4 dKH change I would be concerned about how the sudden changes in KH affect the fish. The best problems to solve are problems you actually have, not problems you are assuming you might run into.
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Right! - which I think translates for me, right now, LEAVE THE DARN THING ALONE! lol

Though I do want to try and have a theoretical understanding of my water, etc before problems happen rather than needing to firefight if/when they do. And this thread has helped with that. I mean, I might need to reconsider C02 if plant growth stalls, for example.

And I am now pondering whether the scoliosis/rickets in my fish could be ameliorated with more calcium carbonate in the water. (Just read an abstract on a medical study on scoliosis in humans using guppies - similar problem of trying to figure ways of managing a genetic disorder.) But then they're currently teetering on overcrowded (again!), so have to rule that issue out first.

Won't be tinkering with the water chemistry until I have a certain reason for doing so, though.
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