Hearing someone knocking on the door, the rest of the store subconsciously turned their heads to look at the door.

Coincidentally, there is another acquaintance.

Electrician Wu stood in the doorway and looked in, and another old man of a similar age was waiting on the sidewalk on an electric car.

"Old Wu, is this here?" the latter asked, his voice high-pitched.

Due to the light outside and the darkness inside, Electrician Wu squinted his eyes and swept everyone's faces in turn, his eyes fell on Zhang Zi'an's body, and he said in surprise: "Hey, the young man is you?"

"Master Wu, you're here, come in...... Is it your friend out there?" Zhang Zi'an greeted him.

Electrician Wu hesitated for a moment, nodded and said, "He is also a retired employee of our factory, his surname is Zhao, and he is a welder." ”

Then, he beckoned to the man outside, "Come in." Lock your car so you don't get stolen. ”

Zhao welder was a thin old man, his teeth were black and yellow because of years of smoking, and he pushed the door in with a strong smell of smoke, and as soon as he entered, he shouted: "Here, Lao Wu, you're not kidding, aren't you? Isn't this a newly opened shop? You see that this thing hasn't been picked up yet! Let's go and find an old shop, I can't believe the new shop, maybe it will close down in a few days!"

With that, he went to pull Wu Electrician.

Wu Electrician was also a little hesitant, but Zhang Zi'an once helped him out of the fish market, so he was embarrassed to leave.

"Master Zhao, right? I completely agree with what you said—however, my shop has been in operation on this street for more than ten years, and it is not a new one!" Zhang Zi'an interjected.

"Isn't it a new store?" Zhao sneered, pointing to the walls and floor, "This freshly brushed latex paint, the smell has not completely dispersed, and it has only been more than a month since the redecoration, you told me that it is not a new store?"

This shop is indeed new, but the shop next to it is also mine, and it has been in business on this street for more than ten years. ”

Zhang Zi'an understands the other party's idea of looking for an old store, even if it is an almighty Taobao, everyone wants to find an old store with high sales to buy things, so he wants to rest assured, and everyone will be pitted together......

Zhao Welder walked out in disbelief, came back after a while, nodded and said, "Okay, count me wrong." ”

Zhang Zi'an sent Lu Yiyun back to see the store and asked, "Master Wu, are you here to see the 24V heating rod?"

Electrician Wu nodded, and his eyes couldn't help but glance at the aquatic creatures that Zhang Zi'an brought back.

"Look at the heating rod, and by the way, look at the fish. He said.

Zhao Welder complained disapprehantly: "Old Wu, I'll just say that you don't spend that unjust money, isn't a heating rod of twenty or thirty yuan the same? A heating rod of a few hundred yuan can raise better fish?" I don't believe it!"

Electrician Wu waved his hand helplessly, "Lao Zhao, don't persuade me about this matter, I have made up my mind, and it is useless to persuade - the problem is not fish, but safety, you are not an electrician, you don't understand how dangerous electricity is." ”

It seems that before they came, Zhao welder had persuaded him more than once, but he was determined to buy a safer heating rod and rejected Zhao welder.

"Tell me about you...... The older you get, the more stubborn you become!" Zhao Welder pointed at him with hatred.

Wang Qian and Li Kun have a lot of opinions about this Zhao welder: You and Master Wu are not a family, people eat your rice, or use your electricity? Can you be so lenient? If you persuade each other again, it doesn't matter if the other party doesn't listen, so why bother persuading you to live and persuade you.

Before he came into contact with high-end aquarium equipment, Zhang Zi'an didn't think that high-end equipment was good, but after he really got in touch, he understood that you get what you pay for, and you get two cents for five cents, but two cents are much more high-end than one penny, and you can't accept it.

He brought a 24-volt heating rod imported from Germany to Electrician Wu, "Master Wu, you can take your time and try it on the spot." ”

Electrician Wu said a little embarrassed: "I won't tell you, I really brought a multimeter to ......."

He took out the multimeter from his satchel, which he didn't bring with him the last time he went to the fish market, but this time he had a heart.

"It's okay, you can try it casually, there is artificial seawater over there, and the conductivity of natural seawater should be about the same. Zhang Zi'an pointed to a drainage bucket placed in the corner of the wall, these artificial seawater were prepared by Wang Qian and Li Kun under his guidance, just wait for today's aquarium to be in place, and after teaching it once, they will do it themselves next time.

"Oh, it's also artificial seawater. Zhao welder said disdainfully: "A few steps away from the sea, what kind of artificial sea water is there?" ”

Zhang Zi'an retorted quietly: "You can't say that, the natural seawater near the shore is inevitably polluted, especially near the city, and it is just a matter of raising ordinary hands-on fish, and it is better to cooperate with artificial seawater for high-grade fish, otherwise it is too distressing to die." ”

Wu Electrician was quite interested when he heard this, he used to pull back the natural seawater from the sea in order to save money, but now he feels that the practice of hand fish can no longer satisfy himself, and he is ready to raise some high-quality fish.

"What about artificial seawater?" he asked.

"The salinity of natural seawater is 34%-35%, prepare artificial sea salt and fresh water, and then buy an ordinary hydrometer, and mix it according to the temperature-salinity-density table attached with the hydrometer. Zhang Zi'an explained briefly, then raised his hand and pointed to the buckets in the corner of the wall and emphasized: "But there are some things you need to pay attention to, that is, when preparing artificial seawater, don't use metal containers, iron, aluminum, copper or anything else." ”

"Because seawater corrodes metal?" said Wu electrician.

"One is because of this, and the other is because after the metal is corroded, a large number of metal ions will enter the artificial seawater you have prepared, and the pollution of natural seawater may not be so heavy...... You see, I'm using the cheapest plastic bucket in the supermarket. Zhang Zi'an gestured.

Electrician Wu took a breath, "If you don't say it, I may really use the iron bucket at home to match, after all, it is strong......"

"Do you have artificial sea salt here?" he asked with interest.

Zhang Zi'an replied: "There are high-end and low-grade ones, it depends on which one you want." ”

"What's the difference between high-end and low-grade?" asked Electrician Wu again.

Zhang Zi'an brought two bags of sea salt for him to compare, "The main components of sea salt are sodium chloride, magnesium sulfate, and potassium chloride, which account for 90%, and the remaining 10% are trace elements - the difference between high-grade and low-grade is here, low-grade sea salt contains more than 20 trace elements, and high-grade can have more than 40 kinds." If you only raise fish, you can buy low-grade ones, and there is no need to waste money. But if you also raise corals and anemones, without enough trace elements, they will not be able to brighten their colors. ”

Wang Gan, Li Kun and Jiang Feifei listened attentively and felt that they had gained a lot of knowledge.