Calcium and pH

[shirley knott]

Hey fellas,

I discovered my calcium was too low (around 300-320), probably because for several months I used R/O water without supplementation. I just started with soft corals, but I need to fix this to expand into the hard coral species.

Therefore a month ago I switched to Red Sea salt, added a mineral additive, and started using a calcium solution on top. Plus I put a couple of dried cuttlefish skeletons in the tank to dissolve, on the recommendatiopn of the fish shop guy. But Ca is still 300. What gives?

My pH is a little low at 7.9, dKH is 10, salinity 30 ppt, ammonia and nitrite zero, nitrate 20, phosphates 0.5.

How are Ca, PO4, pH and dKH linked? Can i rapidly raise the calcium, or will this screw with my other water chemistry? Thanks

Shirley

 

[CZ3]

In loose terms, for ease of understanding and explaining, this is how Ca, pH and Alk are linked. Leave PO4 out of this for now. You can usually target two of the three and have to let the third settle where it falls. This works best. If you fight to target all three then it will be a constant battle that you'll find always has one or two of the three parameters falling off.

For a Reef tank the important two targets are Ca and Alk. Let the pH find its own level when the other two are at your desired amount. That is what happens when using a Ca Reactor. After the reactor is running people begin to fight he pH level which drops. Eventually they give up the fight and find its ok to let the pH fall where it may so long as the other two are on target.

Drip Kalk for top off to replace evaporation. This will target Ca and Alk. Take out the Cuttle Fish. LFS advice is known to be bad. Use Macro Algae to reduce your Nitrates, also reduce your feedings. Run some Phos-ban for two days then remove, and your PO4 level should fall. Be patient and you will see changes in 1-2 months. Also stop the mineral supplements and make sure you do monthly 20% water changes the new salt water replenishes all minerals.

 

[mojoreef]

Check your magnesium.


Mike

 

[plack]

I have no idea if you have: a new or established tank, big or small tank ,allot of sps, or a recently added calcium reactor or why your salinity is down to 30 ppt and your nitrates up to 20 (not so good) but have you checked the new mixed water before adding it to the tank ? most salts have close to enough calcium (if not way too much)I never heard of one so low so could it be the test kit? thats why I suggest you mix up some new salt water to 35 ppt with your new and old salt and check the calcium on them first hope that helps and what do are you using for filtration specifically do you have any bio balls or any floss/sponges that are not cleaned weekly ?
Paul

 

[prow]

I discovered my calcium was too low (around 300-320), probably because for several months I used R/O water without supplementation. I just started with soft corals, but I need to fix this to expand into the hard coral species.

yeah i think your right there. that and what the corals have used up.

Therefore a month ago I switched to Red Sea salt, added a mineral additive, and started using a calcium solution on top. Plus I put a couple of dried cuttlefish skeletons in the tank to dissolve, on the recommendatiopn of the fish shop guy. But Ca is still 300. What gives?

IMO the best salt is instant ocean. the reason is because of the consitancy. most vary alot bag to bag. hard to get a pattern for supplementing. what type Ca+ and how much did you add?

My pH is a little low at 7.9, dKH is 10, salinity 30 ppt, ammonia and nitrite zero, nitrate 20, phosphates 0.5

wow. yup salinity should be 1.025ish. 1.026 would be the highest i would go. not to hard to fix this. to fix all this just do a water change and bring down the salinity, will help with the phos and nitrates too. then check the Ca+ and add Ca+ chloride to bring up the Ca+ to balance with the dkh will need to bring it up to 430ish. this should also take care of the lower ph.

How are Ca, PO4, pH and dKH linked? Can i rapidly raise the calcium, or will this screw with my other water chemistry?

huge question. here are some really good links.
http://www.advancedaquarist.com/issues/nov2002/chem.htm
http://reefkeeping.com/issues/2002-04/rhf/feature/index.htm
http://www.advancedaquarist.com/issues/sept2002/chem.htm http://www.reefkeeping.com/issues/2004-09/rhf/
they all good links with in each article aswell. hope this helps good luck. these are good to keep for referance

 

[plack]

prow_ salinty is in ppt. Specific gravity is what you listed so his 30ppt is about 1.022 specific gravity and is low not high

 

[prow]

oopppsss my bad did not even see that.lol. samething though just adjust up.

 

[MikeS]

The problem with an imbalance like that is that adding addtional Ca may be to no avail, the levels may not rise. When these things get out of balance it can be difficult to raise the lower value....Your best bet IMO is to correct the imbalance by removing the imbalanced water and replacing it with balanced saltwater in a series of water changes.

As stated above, you should try to get your SG up around 1.025-1.026. NSW has a gravity of 1.026 @ 35 ppt salinity....don't be afraid of taking your SG this high, it is after all the environment our corals come from. By keeping your SG at this level, you can maintain NSW values of Ca, alk, Mg, ect, without worrying about messing with your proportions vs. NSW. I'm a big believer in maintaing NSW values when it comes to water chemistry.

Don't raise your SG too fast...a few 10-20% water changes with an increase in gravity no greater than .001-.002 per day should keep you in a safe range.

Here are some good target values to shoot for...

SG 1.025-1.026
Ca 410-420 ppm
Alk 6.9-8.3 dKH
Mg 1250-1300 ppm

Don't forget about Mg, it plays a role in the Ca/Alk balance as well....

MikeS

 

[plack]

I totaly agree and if you have a sump and a fan atop the tank to cool things off and you are getting evaporation just add new mixed water instead of just top off water and it will rise slowly don't try and make it higher just make the new mix to the proper levels and add slowly I lost xenia adding too much

 

[MikeS]

here is a calculator to help you figure the correct balances....

http://home.comcast.net/~jdieck1/chem_calc3.html

MikeS

 

[shirley knott]

goodness, thanks all for the info people. i don't have a test kit for Mg yet, so i can't check that one, but I can answer some of the other Qs:

it's a newish 340L tank (only 4 months old) with an external filter, live rock and coral sand, and a protein skimmer. i was told to keep the phosphate-removing stuff permanently in the external filter, and to add activated carbon to the compartment in the protein skimmer for 3 days a month only: this was local fish shop guy advice, though

i have about 8 fish species, and about 6 soft corals, plus an urchin, shrimps, crabs and snails. once a week i clean the tank, take out about 70L and replace with the same volume RO water to which i've mixed in salt and (recently) also calcium and mineral additives. once monthly i also rinse all the filter material in the external filter in the tankwater i've just taken out. i've been told that RO water does not have a proper measureable pH. also in this thread, people have said that my salinity is either much too high or much too low. who do i listen to?

are the cuttlefish useless, or actually toxic? should i take them out, or doesn't it really matter?

i'll post the exact makes of my calcium test kit (it's the one where you measure the volume of solution C added to make it go blue) and my calcium supplement (a liquid that also contains Str and Mo, apparently 5ml per week per 30gal, so i've been adding 15-20ml a week) when i get home.

thanks all!

 

[shirley knott]

calcium...

okay, i got home and tested my ready-to-go-in bottles of water: they were only 320 calcium themselves, even after i'd added the bottle's stated amount of additive

so i added more salt and calcium supplement to each bottle, such that each new 25L water tub is now about 38ppt and calcium 470 - now at least i'll be putting the average up each time.

the calcium supplement i was sold is "red sea reef success calcium +3" which apparently 'contains blended calcium salts' and is a 'formulated calcium replenisher which combines strontium, molbdenum and iodine in a unique manner such that no cation or anion displacement occurs when added to the aquarium'. it says the dose is '5ml for each 120L of aquarium water per week.'

 

[plack]

As far as salinity if you re-read you will see it is low no disagreements.

As far as ph its really alkalinity you want to watch not the ph and you can pickup reef buffer made by sechem or kent or ? all will work add slowly to ro water then add salt.

Sincen It's a newer tank just worry about getting your new water at the proper levels thats way to high a level for salinity or calcium add more water and get it at 35ppt then add that as stated before.

 

[shirley knott]

that was 20% of the tank volume. i figured that adding this would bring the tank's average figures up, and will check later. did i make a boo-boo?

 

[plack]

It's just that if you bring levels up too fast things CAN DIE.

 

[mojoreef]

Shirley your are running your salinity about 15% lower then what is normal SW concentrations. Normal calcium at 30ppt would be about 350. This would also mean that your alk should also be 15% less then normal, but in your case it is even higher then normal levels at 35 ppt. SOooo you have a huge ionic inbalance in your water, and as you add a calcium suppliment the high alk level is just percipatating out of the water. You wont win this battle.
As mentioned prior the best way to fix is a series of WC (about 20% of the total water compacity) with SW that has a calcium level of around 410, alk at 8dkh and mag at 1190. Also make sure the salinity is at 35ppt. this should get you oout of your problem. Also get the magnesium test as it is a big player in the balancce formula.

hope it helps


Mike

 

[MikeS]

Let's start over from square one here...

Ok...aside from your snails and coralline algae growing on your LR, you basically have a pretty low Calcium usage system going right now. Stop adding any Calcium or alkalinity additives to your tank, let's take care of your imbalance and low SG first (which will in turn help your actual levels) and work from there.

Start doing 10%- 20% water changes weekly...adjust your salt mix to 1.025-1.026 SG., 410 ppm Ca, 2.5 meq/L alkalinity (7 dKH). If you have a Mg test kit, try to adjust your Mg to around 1260ppm. Test the salt mix, adjust it, let it areate for 24 hours then test again to verify.

This solution of saltwater is basically what NSW vaues are. By taking out imbalanced water and replacing it with balanced water at NSW, your tank water will eventually become balanced and atain the correct levels as well.

Once you have a good, balanced NSW value in your tank, you can then begin adjusting your levels accordingly. It's better and easier to start with the correct numbers in the first place and compensate for usage then trying to correct existing large imbalances.

As plack stated above, do not change levels too suddenly, rapid changes in chemistry can have an adverse effect on your livestock. The 10-20% weekly change should be adequate, don't try to tamper with the levels in the tank beyond that.

On the pH of RO/DI...don't worry about it... It is usually around 7, but can dip lower depending on O2 and CO2 levels...your salt mix should bring it up close to where it needs to be.

Let's get your levels correct with water changes and go from there....

MikeS

 

[shirley knott]

thanks all. it looks like i have a lot of reading to do, to understand the chemistry before i can fix it.

to summarise: my water salinity is too low, my calcium is too low, but for some reason my alkalinity is high-normal. i need to get a Mg kit, then my options are to either use calcium chloride as per the calculator, or to gradually replace all the tank water with new water in 10-20% weekly increments, taking 6 weeks or so. a majority has favoured the latter, so that's what i'll do:

i collect my RO water in 20-25L flasks. should i then ...
1. first add the mineral supplement ("Re-Mineral Marine, contains minerals for RO water ..... raises alkalinity .... use 1 spoonful per 15L water") at the stated dose, or less?
2. follow this with the salt (red sea), to a salinity of 35ppt
3. finally add the 'calcium +3' to around 410-420

sounds good?

p.s. one last pointer - way up above i mentioned the other fish shop advice i got about phosphate removers (constant) and activated carbon (3 days a month) ..... but then i read someone say to use phospahe remover for a couple of days only. can someone clear this one up for me?

xxx
shirley

 

[shirley knott]

*bump* anyone who helped me up above (or anyone with a good understanding of reef chemistry) ..... pls help, mixing ingredients standing by i did a fair bit of reading about calcium control and alkalinity, and understand that i need to add them in balance. my replacement water is ready for mixing a volume of water equivalent to 35% of the tank volume - my main question is in which order to add the ingredients to the water. .... (supplementary question, is the more water changed the better, despite the cost and time involved. small and frequent, or big as poss?)


--------------

I have bought a big water butt as a mixing tub for my R/O water, and collected 100 litres of water. my additives are: Red Sea salt (containing presumably some Ca, Mg and other Red Sea salts - hopefully it doesn't vary too much from 25kg tub to tub. i changed to this over a period of 2 weeks from Tropic Marin); Tropic Marin 'remineral marine' for RO water (ingredients not given, but presumably raises alkalinity ..... not sure if it also contains calcium); Red Sea reef success calcium suspension (contains Ca, Str, Mol, Iod, as "blended calcium salts") - a liquid maintenance additive; Salifert Liquid magnesium (contains Mg, Ca and Na as sulphate, bromide and chloride salts). this is again a liquid additive recommended for maintenance, but the shop didn't have any magnesium powder in stock. Oh, and i also have some Calk, ("a balanced formulation of calcium and bicarbonate") but have not opened or used this yet.


help! what order do i add and test? this is my plan, is this right:

1. add salt and test salinity until 1.026 (35ppt) - currently 33
2. test alkalinity and add minerals until dKH 7 - currently 11
3. test magnesium and add supplement to 1260 - Mg currently 1000
4. test calcium and add calcium (?as liquid) until 420 - currently 370
5. retest dKH, Mg, Ca, then bug you guys again for tips!

once i know the amounts add to get 100 litres perfect, i'll know for next time and i can scale down or up. but presumably if i do it in the wrong order, it can cause problems with precipitation etc.

if it helps, my phosphates are at 0.25, nitrates an alarming 20-40, pH 7.9, ammonia and nitrites zero.

shirley

 

[steve-s]

Before you make any additions, get the water up to 35 ppt. The level of the elements will change as the concentration of salt does. More than likely, the original issues with the chemistry are stemming from this.

If afterwards there might be some tweeking to do but you will most likely be left with a slightly higher alkalinity and Ca although Mg might need a hand (should be 3x Ca approx). One thing to keep in mind with your chemistry endevour is there is no need for exact numbers, you only need to be "in range" of balanced levels. When performing your water changes (if this will be a driving source for chemistry control), the water changed out and the new added will only partially increase/change your main display tanks numbers so slightly higher numbers in your new water is beneficial to some degree. It will only work against you if the display has nothing (which I doubt) using the elements.

http://home.comcast.net/~jdieck1/chem_calc3.html

When adding the above items, always start with buffering products (if added to the display, best done in the early AM when pH is at it's lowest point), wait 6-12 hrs, add the Mg wait 6-12 hrs and then the Ca last. If I am correct on what you will eventually be sitting at once the salt is up to 35 ppt, the only thing that may be needed is Mg. Assuming this is all being done soley in a mixing vessel and not in the tank.

As far as your low pH problem, with the alk sitting at 10DKH, I would be looking at your overall set up as aposed to soley relying on the chemistry side. Poor aeration both in the tank/tank room are the major causes of poor or chronically low pH. Tank lid, no sump, lack of surface aggitation, poor room ventilation. There is also overfeeding/stocking, poor nutrient export and so on.

The use of buffers beyond NSW will actually impede proper pH if it gets too high. You end up forcing out all the CO2 and then the tank just sucks it back in causing a pH crash. Look to the tank set up as well as the time of day your testing. pH will be at it's lowest point in the AM and climb throughout the day. Algaes much like your common house plants will sorb CO2 during the photoperiod and expell O2. This naturally increases the pH. As the photoperiod nears it's end, the pH will be at it's highest point. The best time to test is somewhere in the middle of the photoperiod. It's also a good idea to test at the same time relatively speaking to help guage the consistancey of the pH.

Cheers
Steve