Calcium and pH

[shirley knott]

When adding the above items, always start with buffering products, wait 6-12 hrs, add the Mg wait 6-12 hrs and then the Ca last.......

......as far as your low pH problem, with the alk sitting at 10DKH, ......... 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. ......

wow, thanks steve, what a great answer.

overfeeding / overstocking : guilty on both counts. i'll cut down the feeds, but i ain't doing a cull. the wife obsessively buys stock and loves feeding, but she's away for a couple of months, so i can control this at least.
poor aeration : i wasn't aware that the tank needed aeration, but it has a protein skimmer and powerheads. yes, there's a lid. no sump. no surface agitation. poor room ventilation. i didn't know this was trouble.
poor nutrient export pls explain

 

[steve-s]

wow, thanks steve, what a great answer.

overfeeding / overstocking : guilty on both counts. i'll cut down the feeds, but i ain't doing a cull. the wife obsessively buys stock and loves feeding, but she's away for a couple of months, so i can control this at least.

Can you give a rundown of the fish you have, what you feed and how often?

poor aeration : i wasn't aware that the tank needed aeration, but it has a protein skimmer and powerheads. yes, there's a lid. no sump. no surface agitation. poor room ventilation. i didn't know this was trouble.

Not sure on your tank size but I'm fairly certain a single powerhead and skimmer is not fitting the bill. Water flow is important for several reasons but in general you should try to get the overall flow within the tank up to a bare minimum of 10x the water volume, preferabley 15-20x species depending. Surface aggitation is where gas exchange occurs. Rippling the surface water briskly releases CO2 and incorporates O2. If there is a solid lid, CO2 quickly accumulates and supresses pH. The whole tank top does not need to be open to the air but the more the better. Just be mindful of the fish types you have as many can be jumpers.

poor nutrient export pls explain

Nutrient or DOC (dissolved organic compounds) is where the nitrogen cycle starts so to speak. Many incorrectly assume that if the biofilter is functioning correctly it's all good, ie.. no NH3 or NO2 and low NO3. This is where people are lead astray to not doing water changes either. In any event, nutrient export is how these compounds are reduced by removing them. It can be accomplished with a good skimmer, water changes, refugia via macro algae harvesting and the like.

Cheers
Steve

 

[shirley knott]

fish: i have..... two percula clownfish (Nemo and Sushi), a firefish (Grumpy), a yellow sailfin tang (Tango), a yellowtail blue damsel (Pepsi), a ?name rainbow tang (Speedo), a lawnmower blenny (Flymo), a ?name black stripe damsel (Coke), a sea urchin (Chloe), five red-headed gobies (unnamed), two starfish (unnamed), four cleaner shrimps (unnamed), a boxing shrimp (Rollo), a ?name fire shrimp (Garfunkel), an arrowhead crab (Deidre), a pyjama wrasse (Pyjama), lots of red-legged hermits (no names), a blue-legged hermit (Mr Hermit), a ?name blue wrasse (Dude), two ?name blue gobies

soft corals ..... erm, i'm not very good with names, but there's two leather thingies that look like gloves, a clavularia and one that looks similar, two featherduster worms, a sun coral, several mushrooms, and two types of toadstool, one of which is called Afro.

feeding once daily with a frozen cube and a pinch of dry flake. occasionally an extra cube. once a week a couple of cockles. twice a week some marine snow for the corals. twice a week a little packet of bloodworms. it's possible that sometimes my wife feeds extras, especially if people are over.
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tank size - 360 L, single skimmer but 4 powerheads. 3-part lid with gaps. i've religiously changed 10-15% of the water weekly. i'm interested in the "refugia via macro algae harvesting" and would love some hints or links.

thanks matey

 

[steve-s]

fish: i have..... two percula clownfish (Nemo and Sushi), a firefish (Grumpy), a yellow sailfin tang (Tango), a yellowtail blue damsel (Pepsi), a ?name rainbow tang (Speedo), a lawnmower blenny (Flymo), a ?name black stripe damsel (Coke), five red-headed gobies (unnamed), a pyjama wrasse (Pyjama), a ?name blue wrasse (Dude), two ?name blue gobies

Inverts are not a concern when dealing with nutrient "creators" if you will. As far as your fish load goes.... Yikes!!

A loose guideline to follow is one inch of (adult) fish size (not including the tail) for every 5 gallons of tank space. This guideline is affected by many variables so treat as a guide, not a rule. Free swimmers, stationary/territorial, benthic, aggressiveness, eating habits and so on all fit into the "calculation". It terms of shear fish population though you have severely pushed the limit. I would strongly urge you to consider reducing that. Even with a good amount of export/water quality control, as the fish grow they will become cramped for space and aggressiveness will increase. Not to mention there will most likely be health concerns along the way.

In a 360 lt tank (US or Imperial?) you are well (over)stocked for a tank that size. 80-95 gal depending on your calculation gets you somewhere about 18" of fish. The smaller fish are not too much a concern but the two wrasses and the two tangs will be. Both types are extremely active "on the go" fish and will quickly outgrow this setting. I would be wary with the firefish in this setting as well, they are quite timid and generally do not like an active tank.

Have you considered a tank upgrade?

feeding once daily with a frozen cube and a pinch of dry flake. occasionally an extra cube. once a week a couple of cockles. twice a week some marine snow for the corals. twice a week a little packet of bloodworms. it's possible that sometimes my wife feeds extras, especially if people are over.

None of the corals will really benefit from your use of the Marine snow, it will do more to foul the water than actually feed anything. The amount of food your adding in a ddition to the waste produced by the fish load is more than adequate for all except the sun coral. That one needs to be fed meaty foods directly into each polyp head several times weekly. The rest will do fine with what you feed the fish.

On that subject, you are very much overfeeding. Once a day is plenty, especially with the load on your biofilter/lack of export. Mixing the variety of foods fed is a great idea but alternate the types each days feeding instead of adding another feeding/day. Try to avoid dried foods, they are a nasty source of phosphates and probabley the lowest in nutrition, manufacturer depending. Do a search on this site for "blender mush".
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tank size - 360 L, single skimmer but 4 powerheads. 3-part lid with gaps. i've religiously changed 10-15% of the water weekly. i'm interested in the "refugia via macro algae harvesting" and would love some hints or links.

Many posts on this site about that. Also look in the reference section on the home page.

Cheers
Steve

 

[shirley knott]

thank you. all are small (1-2") except the two blue gobies are 3" inch and the yellow tang is 4". i feed the sun coral directly using a syringe/bottle (see pic) as you say, before the rest of the tank gets a look in.

i'm doing three 40% changes over the next fortnight to reduce the nitrates by half, but take all your points on board. i'll look into the refugium/algae harvest thing.

thanks again %^)~